Eight sample stands ranging in age from 2 to 22 years were studied to characterise dry matter, energy, and nutrient contents of the above-ground portion of intensively managed Pinus radiata D. Don plantations on a good site. Site index averaged 36 m at age 20. Dry matter content was closely comparable similar data from Australia. Net dry matter production averaged 14.4 tonnes/ha/annum over the 22-year period

The fibre, beating, and papermaking properties of kraft pulps prepared from red beech (Nothofagus fusca (Hook, f.) Oerst.), hard beech (Nothofagus truncata (Col.) Ckn.), and two silver beech (Nothofagus menziesii (Hook, f.) Oerst.) wood samples were examined. The anatomical properties and chemical compositions of the wood samples and of fibre and vessel elements in wet pulps and in situ in handsheets were examined and related to beating effects and papermaking properties. The effects of pulp beating in a Lampen mill, and in a PFI mill at 10 and 25% stock concentrations were evaluated.

Wood chips from the red beech and silver beech samples had similar densities and similar anatomical characteristics. The hard beech chips, on the other hand, were denser by more than 100 kg/m³ and contained proportionately fewer rays and vessels and more fibres than the silver beech and red beech chips. Methanol extractives, ash, lignin, and carbohydrate contents were similar for the silver beech and red beech samples. The high-density hard beech chips contained more methanol extractives and less lignin than the other species.

Pulp yields, fibre and vessel lengths, fibre and vessel diameters, and chemical compositions were in general similar for the red beech and the two silver beech pulps. The hard beech pulp, on the other hand, had the highest yield, the thickest fibre walls, and the longest and widest fibres and vessels.

Effects of beating on beech fibres were in general similar to those on softwood fibres. Ease of pulp beating was dependent on fibre dimensions, particularly fibre wall thickness, and on the conditions and types of beating. Depending on the species and the degree and conditions of pulp beating, wall material was progressively removed from fibre surfaces, fibrillated, and converted into fines. At the same time, fibre walls were progressively disorganised through the development of wall dislocations and delamination, fibres were made flexible and more able to collapse during papermaking, and fibre configurations (kinking) were modified.

Pulp beating at high stock concentrations selectively caused vessels to become fibre-like and ropy. Thus, pulps processed in this way should not be susceptible to vessel picking from paper surfaces during printing. This conclusion was supported by microscopic examination of vessel configurations in paper webs.

Trends for the strength and optical properties of paper prepared from the beech pulps were found to be generally predictable from a knowledge of their characteristics and the types of beating treatments given the pulps. General trends for the different species and the different beating conditions were similar to those obtained with softwood fibres. The exception was paper tearing-strength which increased rather than decreased with pulp beating. The typically low tearing-strengths of hardwood kraft pulps must be related to the shortness and narrow diameters of their fibres when compared with those of softwood fibres.

Slash pine (Pinus elliottii Englm.) grown in New Zealand is suitable for veneer production, despite the presence of a wide juvenile core of low density, and higher resin content than other pines grown in New Zealand. The green veneer yield was 55.5% of bolt volume, but the yield of A and B veneers was usually low because of the presence of a wide knotty core in late- or unpruned bolts. There was no appreciable degrade after drying, except for end splitting which could be overcome by using a milder drying schedule.

Site index (height of the dominant stand at some specified reference age) is a practical and commonly used method for quantifying site quality in pure even-aged stands. Permanent plot records from Douglas fir (Pseudotsuga menziesii (Mirb) Franco) stands in Kaingaroa Forest were used to compute site index equations. Coefficients for the equation developed are presented, and limitations in the application of the equation are discussed.

Site index (height of the dominant stand at some specified reference age) is practical and commonly used method for quantifying site quality in pure even-aged stands. Permanent plot records from radiata pine (Pinus radiata Don) stands were used to compute site index equations. The data were divided into groups that might exhibit different height-growth patterns, and separate coefficient estimates were computed for each group. Coefficients for the eight groups finally selected are presented, and limitations in the application the equations are discussed.

The fascicle surface area, both for each cluster separately and for the tree by fascicle age class, was calculated for 12 Pinus radiata trees grown under widely different soil-moisture conditions. Four surface-area models and a control method were used. A model based on the square root of the product of volume (or, alternatively, weight divided by fascicle density) and length facilitated precise surface-area determinations, the predictions departing by less than 2% from the control method. The other three models tested incurred errors of 20-50% for individual cluster estimates and 14-25% for tree estimates.

Surface-area estimates were of the structural surface area, and after its definition functional surface area could be obtained as a later step.

The hypothesis that Platypus-associated mortality of Nothofagus spp. is a direct result of the invasion of the sapwood by a fungal pathogen was tested by drilling holes in living red beech (Nothofagus fusca (Hook.f.) Oerst.) trees to simulate Platypus tunnels, and inoculating these with the suspected pathogen — a Sporothrix species. Other trees were inoculated with sterile distilled water and with a Platypus ambrosia fungus, Endomycopsis platypodis Baker et Kregervan Rij. All the Sporothrix-inoculated trees and one E. platypodis-inoculated tree wilted and died. No trees inoculated with sterile water died. Sporothrix sp. was recovered from well above the inoculated zone in all the dead trees, including the E. platypodis inoculated tree.

Within 27 months, infection by species of Armillaria killed 16% of the Pinus radiata seedlings that were planted at 1 x 1 m spacing on a site freshly cleared of indigenous mixed hardwood forest. Mortality was grouped around stumps of Beilschmiedia tawa, suggesting that these were the major inoculum source. Stumps of B. tawa that had borne either sporophores of A. novae zelandiae only or those of both Armillaria species had significantly greater seedling mortality near them than stumps bearing only A. limonea sporophores or with no sporophores, and mortality was significantly greater around stumps with only A. limonea sporophores than around stumps with no sporophores. This difference suggests that A. novae zelandiae may be more pathogenic to P. radiata seedlings than A. limonea, and that porophore presence is an indicator of stump infection. The few stumps of hardwood species other than tawa which bear Armillaria sporophores may also be important sources of Armillaria inoculum. After 27 months, 28% of the living trees were infected with Armillaria and these were grouped around trees previously killed by Armillaria.

Armillaria root rot, caused by either Armillariella novae-zelandiae or A. limonea, is the most damaging disease in Pinus radiata established on sites freshly cleared of indigenous forest by felling and burning. The incidence is related to the composition of the former indigenous cover. Pine planted on sites occupied mainly by Beilschmiedia tawa, Dacrydium cupressinum, mixed hardwoods, Weinmannia racemosa and Nothofagus spp. suffered, respectively, 27%, 19%, 16%, 11% and 5% mortality after 2 years. The mortality was distinctly grouped and may leave by age 6 nearly one-third of the planted area as basically productionless openings surrounded by dead and dying trees. In two severely diseased stands, 15% and 16% of the remaining live trees were infected to a degree shown to significantly reduce diameter growth. This growth reduction is compounded when the trees are also heavily infected with Dothistroma needle blight. A financial analysis indicated that, on a severely affected site, disease increased growing costs (break-even stumpage) by 43% in a 15- or 21-year pulpwood rotation and 37% in a 26-year sawlog rotation. Using a 10% discount rate, the amount that could be spent (without increasing the growing costs) on a hypothetical disease control procedure involving root and stump removal during site preparation, was estimated by assuming various improvements in yield. The model indicated that if control achieved a 60% reduction in disease losses then a maximum control cost of $167/ha, $163/ha and $135/ha was theoretically justified in a 15-year pulpwood, 21-year pulpwood, and a 26-year sawlog rotation, respectively.

In a 2.5-ha area of terrace rimu forest 10 years after the first selection logging, tree losses through windthrow and other causes accounted for 4.4 m³/ha/annum or 72% of gross increment. Regeneration of rimu at 308 stems/ha was sufficient for stand replacement so long as survival and growth rates are good. Growth of remaining crop trees increased by 11% in response to logging but mortality reduced the net annual increment to 1.69 m³/ha. If growth and mortality continue at these rates it will require 62 years before the stand volume returns to pre-logging level.

Several forms of dieback of Pinus radiata D. Don within otherwise highly productive forests on the eastern highlands of New South Wales, Australia, are attributed here to physiological deficiencies of sulphur or boron, separately or in combination. Over this area there is a strong correlation between the incidence of dieback and soils (usually derived from extrusives or weathered granites) which are deficient in either or both of these elements.

Marginal deficiency of either element could lead to the usual dieback symptoms; directly, by degeneration of the vascular system; indirectly, as in the case of sulphur by increased susceptibility and improved trophic conditions for pathogens such as Diplodia pinea. Both the level of deficiency, and the resulting symptoms, are subject to seasonal effects.

Survival and growth of young Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) transplants in the warm, dry-summer climate of Oregon are heavily influenced by competition from grasses and other herbaceous weeds. The ephemeral increase in available soil moisture resulting from weed control reduced tree moisture stress in the summer. This not only resulted in immediately increased growth, but also had significant or highly significant positive effects on tree growth for several years following, hastening the onset of exponential growth and thus shortening crop rotation.

Pinus radiata D. Don callus maintained for 2.5 years by subculturing was observed to differentiate, producing nodules containing xylem, cambium, and phloem. It has been shown that there is a pronounced optimum in the concentration of sucrose and major nutrients for this differentiation. Reduced levels of either sucrose or major nutrients alone were not sufficient to induce formation of this vascular tissue, although simple-pitted parenchyma cells with some secondary walls were produced.

Cuttings of two radiata pine (Pinus radiata D. Don) clones were grown for years in lysimeters. Four soil conditions were used to study the effects of nutrition on tree growth and form — (1) subsoil, kept low in N; (2) subsoil, kept low in P; (3) normal proportions of topsoil and subsoil; and (4) double topsoil volume. The latter increased nutrient supplies — particularly of N. The major effects of N or P stress on the trees were to restrict (1) stem diameter growth more than height growth and (2) branch growth more than stem growth. In contrast, trees with access to the additional nutrients particularly N) in the double-topsoil lysimeters had larger diameters at breast height in relation to height, and larger branches producing considerably greater quantities of foliage each year; however, foliage retention time was decreased.

Almost all published data on hydraulic conductivity (the longitudinal waterpermeability of green sapwood) prior to 1983 are seriously in error because both water permeant and wood specimens were not deaerated. Faulty deaeration procedures affect most subsequent values. The resulting air embolism, already demonstrated for seasoned wood, is found here to affect green (Pinus radiata) sapwood also.

The end-surfaces of permeability specimens need to be cut cleanly to minimise extraneous surface resistance to gas- or liquid-flow. For conifer wood (green or seasoned) there exists a minimum specimen length of about 20 mm below which longitudinal permeability values are greatly excess of the bulk permeability. Furthermore, on air-seasoning, the fraction bordered pits in the earlywood that aspirate is much smaller for a specimen shorter than 20 mm than for a longer specimen. The permeability of such a short specimen may thus be more than one hundred times the bulk permeability of the seasoned wood.

The gas-permeability of an air-dried wood specimen is affected additionally by the moisture content of the wood, the humidity of the gas, and the drying rate of the wood during seasoning. Because the drying schedule has to be specified, gas permeability values are of limited usefulness.

A field lysimeter was used to record the seasonal incidence of deep seepage in a yellow-brown pumice soil planted with Pinus radiata D. Don. The volume of water which percolated to a depth of 2.7 m was recorded daily; bulked weekly samples were analysed for nutrient content. The study covers two separate periods of observations:

(1) 1962-64 (begun within a year of establishment of a second pine crop when the ground was still largely bare), and

(2) 1967-73 (initiated soon after canopy closure, by which time a litter layer had accumulated over the entire soil surface).

The deep seepage which invariably occurred each year indicates that the soil mantle is fully recharged annually. The lysimeter discharged percolate in September and October of each year and, more often than not, in August and July; discharge in the January to April period was unusual. The lysimeter index of deep seepage, which ranged from 54 to 573 mm, was closely correlated with gross annual precipitation; differences in the latter accounted for 99.8% and 65% of the variation in lysimeter discharge for the earlier and later periods respectively. Differences between gross annual rainfall and yearly deep seepage ranged from 973 to 1577 mm for the first period and from 1118 to 1555 mm for the second, and may be accounted for by evapotranspiration and changes in soil moisture stored.

Average annual leaching losses, based on the 7 years of data relating to established stand conditions, were (kg/ha): Si 39, Na 12.5, Ca 5.7, CI 5.6, K 4.2, Mg 1.6, and P <0.01; no loss of inorganic nitrogen was detected.

This paper describes the recent changes in density and local distribution of the commercially hunted red deer population in the lower Arawata Valley, South Westland. It is based on five annual (1972 to 1976) remeasurements of 986 permanently marked pellet sample points representing all of the forested and subalpine parts of the deer range. The study area was divided into five altitudevegetation strata in the analysis.

There was an average reduction in pellet group density of 11.2% of the surviving population per annum, and a total reduction of 38% for the four years. Densities were reduced at different rates in the five strata. The largest changes occurred in the sub-alpine scrub and grassland (by 28.3% per annum), where deer are most vulnerable to helicopter hunting, and on the adjacent forested upper valley slopes (by 13.8% per annum). Reductions on the forested valley flats and slopes below 600 m were much smaller (averaged 4.9% per annum), and together contributed only 37%? of the total. In 1976, pellet densities ranged from 40 groups/ha in the subalpine scrub and grassland to 302 groups/ha in the forested lower valley slopes.

The overall reduction in deer numbers attributable to commercial hunting in the Arawata Valley was around 72% since 1969, and in the order of 80 to 95% since the start of helicopter hunting in the mid-1960s.

Samples of radiata pine (Pinus radiata D. Don) sapwood at six moisture content levels from 25% to 50% were treated with a proprietary copper-chromearsenate preservative at concentrations of 2% and 4%. Simple linear regressions of preservative retention on moisture content were highly significant.

The claim that timber with moisture content greater than 30% can be treated to obtain adequate retention to meet Timber Preservation Authority standards is conditionally supported, but is probably not practical in commercial plants.

The effects on paper strength and optical properties of blending unbeaten and beaten radiata pine kraft pulps have been examined. Various proportions and combinations of unbeaten, lightly beaten, or heavily beaten pulps were blended with a series of pulps which had been beaten to different levels.

The addition of from 10 to 30 percent of unbeaten corewood or slabwood fibre caused handsheet tensile strengths and extensibilities to be substantially increased when compared at the same sheet densities. Tear/tensile strength relations were unchanged by the addition of unbeaten fibre, although an apparent drop in tearing strength occurred for given sheet densities. The effects of adding lightly or heavily beaten fibre to blends of unbeaten and beaten fibre were to decrease strength improvements brought about by the presence of unbeaten fibres.

Some possible commercial implications of the study are discussed and include the suggestion that papers could be produced with conventional strengths but with lower-than-normal basis weights or higher-than-normal opacities. It is envisaged that the addition of unbeaten fibre to beaten pulps could lead to the production of more usable paper from less wood, and possibly with the use of less energy.

Analysis of data collected for the period 1965-66 suggests that, with the recent high price for export logs, New Zealand's comparative advantage currently lies in the export log trade rather than in a wood processing industry. Consequently no system of differential stumpages favouring wood processing can be justified on the grounds of tariff compensation.

Timber grade results from 25-mm thick boards from 24 pruned and 12 unpruned butt logs of Pinus radiata D. Don from a 19-year-old regenerated stand thinned twice to a final crop stocking of 392 stems/ha and pruned in three lifts to c. 6 m, were obtained for 2.44-, 4.27-, and 5.49-m log lengths. Log taper was unaffected by pruning. The defect cores were extensive in pruned trees, and bark crescents above steep-angled branches were the worst defects in the unpruned trees. The greatest gain from pruning was the increase of cuttings (Factory) grade, except in the 2.44-m logs where the highest recoveries of clears (13 to 27%) were obtained.

Pruning costs to 5.5 m and compounded at 10% were from $1.37 to $1.77 for trees of from c. 31 to 54 cm final diameter at breast height, respectively. Pruning to 4.27 m was generally the most profitable lift; internal rates of return were from 8.8 to 17.6% for trees of these diameters.

Resin pockets, not obviously connected with pruning, were common in four trees and can confound other grade conclusions.

Adult material (grafts) of Pinus radiata D. Don was grown in a heated glasshouse for 19 months, starting from mid-winter. From mid-summer to mid-summer half the material was given continuous supplementary incandescent light and half kept in ambient photoperiod (Burdon, 1974). All material became largely disentrained from the normal seasonal growth rhythm, and in both treatments pollen cones started to become visible during spring instead of during late summer.

In the second summer the plants with unseasonably formed pollen cones were moved outdoors. However, there was virtually no pollen shedding from mid-summer until close to the normal pollen-shedding season in late winter, even from pollen cone clusters which had started dehiscing before this period. On some shoots two successive pollen cone crops had appeared several months apart but dehisced at almost the same time (Fig. 1).

It appears certain that during autumn there was a powerful inhibition of pollen shedding by some factor or factors of the external environment. This prolonged inhibition could be explained in terms of an effect of decreasing photoperiod (cf. Jenkins et al., in press.) rather than of absolute daylength or of any particular temperature regime.

The early growth from cuttings of 51 Salix matsudana x alba hybrids was compared with that of their parents in a two-year clonal test. From measurements of growth rates and foliation date, estimates of clonal differences, clonal repeatabilities and clonal and phenotypic correlations between characters were made.

Many of the hybrids were considerably faster growing than their parents, in some cases more than 100% for diameter and 30% for height over the higher parent at age two years. There was substantial variation between clone means and clonal repeatabilities were moderate to high.

There were high correlations between first and second year diameters, as well as between first and second year heights of trees grown from cuttings. Ortet height and diameter at two years showed some correlation with first and second year height and diameter of the cuttings. There was no correlation between diameter (first and second years) and foliation date. These hybrids appear promising for soil conservation and river protection planting.

Numerous adventitious buds were induced when fully developed embryos of Pinus radiata were placed on a nutrient agar medium containing cytokinin. The adventitious buds formed directly from the cotyledons and hypocotyls, and often also from meristematic tissue proliferating from these. The meristematic tissue has been maintained in culture for 6 months and still gives rise to many more adventitious buds. The buds, when separated and grown individually on a medium without cytokinin, developed into well-formed shoots. These rooted after approximately 6 months in culture and have developed into sturdy plants.

The effects of removing foliage of specific ages in 5-year-old trees of Pinus radiata D. Don (a) in spring, and (b) at different times during the growing season, were measured in terms of the response through the following 2 years in ring width, percentage late wood, wood density, and tracheid length.

Removal of 1-year-old needles was nearly as severe a treatment as defoliation of the current year's needles, both of which resulted in a very significant reduction in diameter growth, accompanied by an increase in wood density and tracheid length at breast height. The timing of the treatments during the growing season had no detectable effect on density or tracheid length in the wood samples examined.

Pinus radiata D. Don plants (seedlings; and rooted cuttings of two size-classes from semi-adult trees) were grown in the DSIR climate laboratory under different photoperiod treatments. The study was begun just prior to the summer solstice and ran for two consecutive 16-week treatment periods. The eight treatments included combinations of increasing, decreasing, constant long 16-h), and constant short (8-h) photoperiods.

Height increment showed marked differences between treatments. Although differing in pattern of height increment, the three classes of plant showed definite similarities in response to the various treatments. Short days and decreasing daylengths gave reduced height increment compared with long days. Maximum height increment and branch elongation were observed with increasing daylength followed by sustained long days. The responses to photoperiod were evidently superimposed upon an underlying tendency for elongation to occur flushes interspersed with comparative rest periods.

Diameter growth showed less-pronounced differences between treatments and showed no clear parallel with height increment responses to photoperiod. There appeared to be some tendency for greater diameter increment to occur under decreasing photoperiod. The wood quality parameters associated with tracheid dimensions differed significantly between treatments. There was a tendency towards latewood characteristics in material with less active shoot elongation, i.e., short or decreasing photoperiod treatments, although not all treatment differences could be explained in terms of this effect.

Overall, there appeared to be a response to daylength shift over and above any response to absolute daylength.

The outputs of water, suspended and dissolved material, and phosphorus (P) and nitrogen (N) forms from a small (10 ha) catchment under indigenous forest were studied for a period of one year. Streamflow and rainfall records indicated that approximately 14% of total rainfall was discharged as streamflow. The output of suspended sediment was 120 kg/ha, and the dissolved load 226 kg/ha. Much of the P and N output was associated with sediment. Of the annual loss of total P (0.2 kg/ha), 52% was in particulate form. The catchment appeared to be slightly conservative of P and strongly conservative of N.

Recent soil surveys connected with plans to utilise West Coast beech forests have covered areas from the Mokihinui River to Hokitika at more detailed scales than were previously available. Seven main soil groups have been recognised; their properties are briefly described. Four major Pedological trends have been identified in the region. These are:

1. Increasing incidence of gley soils on low glacial outwash terraces with increasing rainfall.

2. An increase in gleying in hill and steepland soils with higher rainfall, coupled with microtopography and parent material contrasts.

3. Increasing tendency for soil and geological instability with increasing angle and length of slope on certain rock types, possibly coupled with higher rainfall and changes in land use.

4. Contrast in types and down-profile movement of organic matter associated with different forest types, mainly beech/podocarp and podocarp/hardwood forest.

Trend 1 has already been largely recognised in planning for potential use for forestry. Trend 2 is reflected by differential growth in some areas already planted in exotic forest. Trend 3 is of major significance in making wise land use decisions. Trend 4 is of relevance in methods of land preparation and in management of protection forests.

In 1981 a lysimeter was designed and constructed so that studies could be made of the quantity and chemical content of soil water draining beyond the tree rooting zone in Kaingaroa State Forest. An 8.5-m² concrete collection pad was built at a depth of 2.7 m with a pipe leading to an instrument hut 9.6 m away. After the pad had been covered with a plastic sheet, the multilayered pumice-ash soil profile was replaced and compacted over it and the surrounding excavated area. Pinus radiata seedlings were then planted.

A strong relationship exists between solar radiation, resulting subcortical temperature of the tree host, and rate of development and growth of the introduced cerambycid Arhopalus ferus (Mulsant). The larval, prepupal, and pupal stages are shorter in duration at elevated temperatures. Adult emergence patterns appears to be determined by the time of larval entry into the prepupal stage which is in turn determined by prevailing temperatures.

The degree of exposure to solar radiation in the field may play a role in determining whether the insect's life cycle extends over 1 or 2 years.

Forests in the Hope River catchment in North Canterbury were classified into five associations, using a combination of Sorensen's 'k' index of similarity and a group average clustering procedure. The composition, structure and habitat of each association is described, and the ability to regenerate is related to stand parameters and regeneration frequency.

Analysis of faecal pellet counts was used to determine the status of red deer, opossum and hare, and their relative density for each association and for geographically denned sampling blocks.

The high altitude mountain beech forests are in good condition with adequate regeneration. Forests dominated by red beech are in good condition in the upper valley, less so in the lower valley.

Radiata pine (Pinus radiata D. Don) veneers treated with copper-chromearsenate preservatives by the momentary immersion method had salt retention inversely proportional to veneer thickness. In plywood made from CCA-treated veneer glued with a phenol formaldehyde resin, shear failing loads decreased with increasing levels of preservative retention, but bond strengths were acceptable up to treatment levels of 10kg/m³. Urea-formaldehyde resin joints failed due to pre-cure.

A continuous indentation method has been used to obtain values for the Young's moduli of lignins extracted from Pinus radiata D. Don wood by the periodate, Klason, and dioxane processes. The periodate lignin, which is considered to be similar to in-situ lignin, was considerably stiffer than the other two lignins at all moisture contents. Values obtained for the Young's modulus of periodate lignin ranged from 6.6 x I0⁹ Pa (at 3.6% moisture content) to 2.8 x I0⁹ Pa (near saturation moisture content).

Compression wood (c.w.) in 40-year-old Pinus radiata D. Don is described. Both cambial age (number of rings from the pith) and visually assessed severity were related to its anatomical and shrinkage characteristics. Because c.w. frequently finds its fullest expression in corewood, further observations were restricted to 8-year-old trees for which some results were available of stem deviations from vertical and their subsequent recovery. Some of these stems had "over-corrected" an initial lean, and resultant c.w. formation was often more severe than that evinced by the original toppling.

All visual grades of c.w. were examined, from intermittent discontinuous crescents of slightly darker wood to very dark c.w. that occupied the entire annual growth layer radially and more than one-quarter of its circumference. Certain of the commonly accepted anatomical characteristics of c.w. were not consistently present in c.w. zones. Among all grades of c.w. intercellular spaces occurred in some samples but not in others, and a degenerate residual S3 layer was occasionally detected under polarised light microscopy and scanning electron microscopy, though less frequently in the more severe grades.

Within the corewood zone, visual grade of c.w. was little guide to its shrinkage behaviour. The regressions of longitudinal shrinkage on microfibril angle were steeper in c.w. than in normal wood, particularly when visual grade of c.w. was severe, but there was little difference in mean microfibril angle between c.w. and the corresponding opposite wood. Within a given visual grade of c.w., microfibril angle accounted for about one-third of the observed variance in longitudinal shrinkage. Much of the remainder appeared to be related to the degree of cell wall thickening associated with c.w. formation — dense c.w. with thick cell walls tended to shrink more longitudinally than c.w. of the same grade and microfibril angle in which cell walls were little thicker than in normal wood.

Two experiments were done to study the effect of leaf wetness on infection of Pinus radiata D. Don by Dothistroma pini Hulbary. In the first experiment, inoculation with D. pini conidia was followed by: continuous leaf-wetness for 92 days; short leaf-wetness periods of up to 8h interspersed with 24-h dry periods; a 24-h dry period followed by continuous wetness for 91 days; no wetness period at all. Infection, as evidenced by stromata of D. pini, was seen in all treatments but the percentage of infected needles was low except in those treatments in which continuous leaf wetness was provided for 91 or 92 days. In the second experiment inoculated foliage was allowed to dry for periods of 0, 2, 7, 14, 30 and 60 days before it was remoistened. The percentage of infected needles was highest in plants given the 0-, 2-, and 7-day dry periods, followed by those given the 14-day dry period treatment, and it was lowest in plants receiving the 30- and 60-day dry periods. The pre-reproduction period of the fungus was 19-21 days on plants given the 0-, 2-, 7- and 14-day dry period treatments; it was 35 and 70 days respectively on plants given 30- and 60-day dry periods. In the treatments involving 7- to 60-day dry periods, stromata were noticed within 10 days of rewetting of foliage. It appears that stromata formation, rather than germination and penetration, is inhibited by the absence of leaf surface moisture.

Water suspensions of fragmented mycelia cultured from single-ascospore isolates of Phaeocryptopus gaeumannii (Rohde) Petrak were used to inoculate foliage of seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco). Infected 0- to 1-year-old foliage on inoculated seedlings was retained to the same extent as uninfected foliage on control plants. On the other hand, the inoculated seedlings retained a significantly lower proportion of 1- to 2-year-old needles than the controls (with one exception) 19-23 months after becoming infected. Infected 0- to 1-year-old foliage photosynthesised at a lower mean rate than uninfected needles of the same age. Despite these effects, no significant differences in total seedling dry weight were found between control seedlings and seedlings infected for 19-23 months.

Seedlings were raised under routine nursery conditions and subjected to a variety of root wrenching and fertiliser treatments. Planting stock characteristics were determined at time of lifting using routine grading criteria. Increased wrenching frequency reduced seedling size, shoot moisture content and foliage concentrations of nitrogen and phosphorus but improved other aspects of seedling quality.

Field performance of planting stock was determined for two planting dates on a moderately severe site prepared for routine plantation establishment. Tree survival, size and form were improved by moderate wrenching treatments and these improvements were still evident in the fifth year after planting.

Mid-autumn planting produced the most distinct differences between unwrenched and wrenched stock. Differences were less marked for mid-winter plantings but wrenching still reduced the incidence of leader damage from 70 to 5%. Unwrenched stock displayed a high incidence of multileaders at two years as a result of initial leader deaths but rarely did this malformation persist at five years after planting.

The forests of the Waitaki and Lake Hawea catchments have been divided into 12 associations using a combination of Sorensen's 'k' index of similarity and a group average clustering procedure. Four associations are dominated by mountain beech, three by silver beech and five by mountain beech and silver beech together. The composition, structure and habitat of each association is described.

Forest health was determined by using the stand parameters of basal area, stem density, mean stem size, diameter size class distribution and regeneration frequency. It was concluded that with the exception of the Tasman catchment the forests are approaching a state of overmaturity, especially in the Dingle and Timaru River catchments where mean stem size is larger and stem density smaller than elsewhere. Further, in these catchments, the basal area is much lower than in the remainder of the survey area, suggesting that deterioration of the stands is occurring. As yet this is not being compensated for by an increase in regeneration.

A rapid method for the propagation of poplars by tissue culture has been developed. In comparison with conventional practices very large numbers of rooted plants can be rapidly formed from small explants and the potting mix can be manipulated to give establishment advantages to the tree when planting out. The technique also gives a method for the international exchange of poplar material under sterile conditions, to eliminate the danger of disease introduction, in a form that can bs quickly bulked up at any time of year.

The buffer capacity measured at pH 6.2 of aqueous homogenates of 1-year-old needles from Pinus radiata D. Don trees aged 5, 10, 15, 20, and 40 years increased with tree maturity. Dothistroma pini Hulb. cultured on needle-extract agar did not show any tendency to optimise the pH of media with varying hydrogen ion concentration. The high buffer capacity of mature-tree needle homogenates does not appear to be a property directly related to mature-tree resistance to D. pini.

Strobili of Pinus radiata D. Don were receptive over a total period of 5 weeks, but within that time there was variation between clones and between successive cycles of a shoot. Individual cones remained receptive for 2 to 13 days; cone closure occurred after rain. Pollination drops were observed in humid conditions only. Pollen movement in an artificial drop was by flotation but, in vivo, nonfloating pollen was also transferred to the micropyles.

Pollen can move into the micropyles before the cone scale complexes have visibly separated, but most is progressively transferred from the micropylar arms during a period lasting 12 days from the onset of visible cone receptivity. Individual ovules can put out repeated pollination drops.

The capacity of the micropyle limits the amount of pollen which can reach the nucellus and germinate. Within a cone, micropyle size varies according to the position of the ovule; ovules further from the apex of the cone tend to have smaller micropyles. Mean micropylar capacities also vary between and within clones. When the total pollen caught in a cone averaged some seven pollen grains per ovule, most micropyles were completely filled.

Three needle characters were studied in 10-year-old Pinus radiata D. Don trees of mainland California origin growing in Kaingaroa Forest. In all, 238 trees from 10 families within subpopulations x 5 subpopulations within populations x 3 populations were sampled. No differences between subpopulations within populations were detected for any of the traits, in contrast to a previous study within natural stands. The populations differed strongly in needle length, rather less in fascicle dry weight, and not significantly in weight/length ratio. The Cambria population had the longest needles and the Ano Nuevo population the shortest, although in the natural stands longer needles had been observed at Ano Nuevo than at Monterey. It appears that results from within natural stands largely reflected environmental effects.

The development and biology of the introduced cerambycid Arhopalus ferus (Mulsant) is discussed. This insect was first discovered in North Auckland in 1963 and since that time has spread throughout the North Island and is also found at various locations in the extreme north of the South Island.

The duration of the life-cycle is either 1 or 2 years and is influenced mainly by the stage at which larvae destroy the subcortical zone and are forced to move into the sapwood, and by temperature. In heavily attacked material, where the larvae move into the sapwood early in their development, severe damage to infested logs can occur within 12 months.

This study suggests that A. ferus may cause severe economic loss during the salvage of windthrown or fire-killed trees.