Cuttings of radiata, pine were grown for six years in wooden containers set in the ground. Three clones were grown under seasonal water deficits (soil water potential —10 bars), but at other times natural soil moisture was maintained as necessary at a soil water potential of not less than —0.5 bars. Seasonal deficits were applied during the periods June-November, December-May or throughout the whole year June-May, using a factorial design. Two of the clones were also grown under four different soil nutrient conditions: (i) N deficient, (ii) P deficient, (iii) normal soil of average fertility, (iv) double topsoil with unrestricted root access to subsoil.

The effect of periodic moderate moisture stress on wood properties was to induce the formation of frequent narrow false rings. These increased minimum (ear Iy wood) density, mean density and late wood ratio in the affected growth layers. Tracheids were also shorter in the outer growth layers of trees grown under moisture stress.

The effects of soil nutrient status on wood properties were small. Pith diameter was larger in the fast-growing trees in double topsoil than in the slow-growing trees with mineral deficiencies. The fast-growing trees also had slightly lower average wood density towards the base of the stem than the other three treatments. Phosphate deficiency produced high late wood density only in the outer growth layers.

Wood density, pith diameter and tracheid length differed consistently between clones. No effects, either clonal or environmental, were detected in development of spiral grain.

Because many of the apparent responses of wood properties to environmental stress appeared only in the outer growth layers of these young trees, it is suggested that, whenever possible studies of the physiology of xylem formation based on young-tree material should be extended to older trees in order to ensure that the same responses are obtained in outerwood formation.

Wood properties were measured on 10 nine-year-old trees from each of the four spraying treatments (aqueous solutions of copper-based fungicides) applied to control Dothisfroma pini infection of radiata pine in Sample Plot R919, Kaingaroa Forest. Wood samples were cut from levels in the stems corresponding to seven and four annual growth layers, and these were examined for wood density, shrinkage, green moisture content, growth rate, tracheid length, grain angle, resin content, pith diameter and bark thickness.

Significant differences in wood properties that could be related to the spray treatments were limited to some loss of diameter growth in unsprayed, heavily defoliated trees (more apparent in the upper than in the lower stem), and also a trend to increasing wood density in outer growth layers following severe defoliation.

Solutions of alkylammonium compounds were modified by addition of various levels of acid (HC1) or alkali (Na₂C0₃). Solution concentrations were designed to provide sub-toxic retentions of the alkylammonium compounds in treated poplar or pine wood blocks. The effect of acid or alkali addition to treating solutions was determined through increase or decrease in decay after treated wood was incubated with test fungi (brown-rot, white-rot, and soft-rot). Addition of low levels of acid (0.025-0.1% w/w HC1) improved performance against basidiomycetes, and to a lesser extent soft-rot fungi. Addition of high levels of acid (1% w/w HC1) further improved soft-rot control, but resistance of treated wood to basidiomycete attack was reduced. Addition of alkali to treating solutions generally led to increased loss of wood substance when treated wood was exposed to fungal attack. Results are discussed in terms of the effect of acid and alkali on the fixation process and subsequent macro- and micro-distribution of alkylammonium compounds in wood.

The acetate salts of seven tertiary amines, which provided a series of increasing alkyl chain length from C₈ to C₁₈, were screened for fungicidal effectiveness against basidiomycetes and soft-rot fungi in pine and birch timber respectively. Dodecyldimethylamine acetate was the most effective against basidiomycetes (toxic threshold 1.6-3.2 kg/m³). Tetradecyldimethylamine acetate was the most effective against soft-rot fungi, but some decay (mean loss of wood substance 3.1%) occurred at 6 kg/m³, the highest level tested. Decreasing alkyl chain lengths (below C₁₂), greatly reduced effectiveness whereas increasing alkyl chain length (above C₁₄) caused only a gradual reduction in fungitoxicity.

Laboratory decay tests show that the fungicidal activity of alkylammonium compounds (AAC) used for the control of wood-decaying fungi can be markedly affected by changing the nature of the anion used.

Amine salts formed from weak acids (e.g. naphthenic acetic acid) show significantly greater effectiveness than those formed from strong acids (e.g. hydrochloric, hydrobromic acid). Enhanced fungicidal activity is ascribed to improved macro- and micro-distribution of the preservative due to a slowing in the rate of the ion-exchange fixation mechanism.

Two experiments were carried out to evaluate the "Pilodyn Wood Tester"

The relation between the anatomy and basic density of Cocos nucifera has been determined using material from the stems of a young, mature, and an overmature palm. Changes in basic density within the stem and with age are almost entirely due to the relative abundance of sclerenchyma fibres and ground parenchyma cells and to changes in cell wall thickness, as both cell types retain their vital functions and continue to lay down additional cell wall material for a very long time at all positions in the stem. The variation in both cell types is illustrated with scanning electron micrographs.

In a 15-month study, mature-length foliage samples were collected at 2-3 week intervals from the lower branch clusters of cuttings of nine non-select Pinus radiata clones. The cuttings which had been planted out four years previously were growing on a uniform pumice soil site at Rotorua.

Foliage samples representative of each clone on 25 sampling dates were analysed for 10 nutrient elements. Analysis of variance of the foliar data indicated that, despite the confounding for ramets within clones and dates, the effects of date and clone respectively were in almost all instances very highly significant (p < .001). In order of magnitude, the fractions of total variance accounted for by clone were: .48 (B), .37 (K, Zn), .23 (Ca, Mg), .12 (Mn), .07 (Na), .09 (N), .04 (P) and .02 (Cu); those accounted for by sampling date were: .77 (Cu), .68 (N), .60 (P), .54 (Na), .41 (Ca), .37 (Mg), .29 (Mn), .22 (K, B), and .11 (Zn).

Clonal repeatabilities as at any given date varied greatly with element, being highest for B and K (.60, .46), intermediate for Zn, Ca and Mg (.39, .37 and .35), low for N and Mn (.26, .17) and very low for Na, Cu and P (.11, .06 and .05). Clone-season interaction appeared to be minor. Tree-to-tree coefficients of variation also varied widely with element and were (in order of magnitude): .32 (Na), .30 (Mn), .26 (B), .25 (Zn), .22 (Ca), .20 (Mg), .14 (K), .12 (P, Cu), .09 (N). To detect differences (p < 0.05) of at least 20% between the means of two sample populations for macronutrients would evidently require sampling from at least 10 trees per composite population; for micronutrients the number generally seems higher (c. 15-20).

The diffusate electroconductivity technique of evaluating cold injury was studied on radiata pine seedlings subjected, at different times throughout the year, to below-freezing temperatures in a controlled environment frost room. The seedlings developed natural hardiness in May which increased to a peak in July to August when experimental frosts of —9° and —12°C caused little damage. Thereafter the seedlings lost their winter hardiness through September to November and returned to the summer minimum of —3° to —6°C. Relative electroconductivity values determined on upper stem tissue, within three days of the low temperature treatments, were in close agreement with visual assessments made one month later when the damage symptoms had had time to develop. Relative electroconductivity values of 0.5 or greater indicated that the low temperature treatment had been severe and would lead to subsequent death of the seedling.

The technique was also used to examine the influence of the number of frosts at any particular low temperature on seedling damage. Where the treatment temperature caused little damage (i.e. slight burning of needle tips) there was no increase in damage in response to the number of frosts the seedlings received. However, where a single low temperature frost caused considerable damage (i.e. many needles and buds killed), the amount of damage increased in response to an increase in the number of frosts. Damage assessment by the electroconductivity method again closely agreed with visual assessments.

A comparison was made between amounts of exchangeable (extracted by 1_MNH₄OAc, pH7) and Bray (0.1_M HC1 + 0.03_M NH₄F) extractable K, Mg and Ca in the topsoils of 128 forest soils and their relationships to levels in the foliage of Pinus radiata growing on these soils.

Amounts of K, Mg and Ca removed by a 1-minute extraction with the Bray solution were quantitatively similar to and closely correlated with amounts extracted by NH₄OAc (r = 0.914, 0.899 and 0.762 respectively). Increasing the extraction period with the Bray solution to 30 minutes had negligible effects on amounts of K but increased the amounts of Mg and Ca extracted, particularly from less weathered soils.

Potassium extracted by all three methods was significantly correlated with foliar K but explained only 9 to 12% of its variation. Correlations between foliar Mg and Ca and amounts of these cations extracted by the three methods were non significant although significant relationships were found within a few specific soil groups. It was concluded that, until such time as soil tests are developed and calibrated which give a good indication of tree-available K, Mg and Ca, the Bray 2 (1-minute) extraction can be used just as effectively, and more rapidly, for characterising exchangeable cations in forest soils as the NH₄OAc extraction.

Kauri seed will germinate between 10.5° and 36°C. However, for raising seedlings, germination and initial growth is adequate only between 19.5° and 27.5°C. The optimum temperature is at, or close to, 25.0°C.

Foliage biomass of five 53-year-old Douglas fir trees was assessed by regression analysis. The biomass of the measured tree components of total foliage, current-year foliage, twigs and branches were all most strongly correlated with tree stem diameter below the lowest living branch.

Needle retention was low, with only a trace of five-year old needles found and 67-82% of the total foliage held as current and one-year-old needles. Needle biomass was estimated at 7.8 tonnes dry wt/ha with an annual production of 2.6 tonnes dry wt./ha.

Predictive equations are developed which could be used to establish a current norm for foliage biomass of Douglas fir in northern Kaingaroa State Forest.

The longitudinal permeability of four 27-year-old trees of radiata pine (Pinus radiata D.Don) was measured by passing deaerated water through de-gassed green wood specimens 20 mm long. Significant permeability differences were found between trees, and there was a negative correlation between longitudinal permeability and density. The longitudinal permeability of sapwood increased significantly with height in the stem from the butt to just below the crown. No consistent pattern of variation was observed with radial position over a cross-section. This is attributed to the relatively large fraction of the permeation area in the outer sapwood that is occupied by latewood, and to the presence of compression wood. An abrupt decline in permeability occurred at the boundary between the wet sapwood and dry wood zones. Results were in general agreement with those of comparable studies on other species.

Earlywood and latewood of both a 19-year-old and a 45-year-old Pinus radiata tree had similar extractives content and composition. However latewood in the heartwood had more extractives than earlywood in the same annual growth ring. The additional extractives are resin acids which probably arise from enrichment of this latewood tissue with resin acids long after the heartwood is formed. No significant differences were detected in the compositions of the fatty and resin acids present in the earlywood and latewood.

The impact of silviculture on intrinsic wood properties can be estimated by separating the analysis into two stages: predicting the impact of silviculture on the distribution of volume according to the physiological age of the wood; and predicting mean-tree wood properties from the mean physiological age of the tree.

A simple growth model provided satisfactory estimates of mean physiological age of trees in two heavily thinned plots of Pinus radiata D.Don. The model was used to predict the mean physiological age of trees from selected regimes.

The usual statistical sampling technique of choosing a sample size to produce an estimate with a specified error limit can be improved upon in situations where indirect costs resulting from estimation errors can be evaluated. The estimation of the weight to volume conversion factor in weigh scaling is such a situation and this paper presents the formulae needed to determine sample sizes that will minimise total scaling costs for both simple random sampling and stratified random sampling. Using cost and production data that is representative of weigh scaling for a New Zealand Forest Service conservancy, the minimum total scaling cost strategy is compared with the 2.5 percent error strategy in terms of sample sizes, variable and total scaling costs, and standard error attained. The comparisons illustrate the differences between the strategies when considering various stratum classifications and stumpage rates.

The minimum total cost strategy produces significant savings compared to the current method and produces more accurate estimates (i.e. smaller standard error) of more valuable forest products which is an intuitively desirable characteristic.

Two-way volume formulae for nine indigenous species or crop types have been developed from earlier data on sectionally measured trees.

The effects of windrowing and skid site formation on site quality were examined in a 7-year-old, second rotation Pinus radiata stand growing on a yellow-brown pumice soil.

Four site types were recognised — normal cutover, windrow, inter-windrow and skids. Standing volumes, after first thinning to 573 stems/ha, were 34.3, 40.7, 20.5 and 5.2m⁸/ha respectively. Relative to the normal cutover the overall windrowed area contained 7m³/ha less volume or the equivalent of a reduction in Site Index (mean top height in metres at age 20 yrs) of 2 m.

Analysis of current season's foliage showed that N and B concentrations were lower on both skid and inter-windrow sites than on the windrow and normal cutover sites. Magnesium concentrations on the inter-windrow site were significantly lower than those on all other sites.

Levels of total N and exchangeable Mg were lower in the skid site and inter-windrow soil profiles than in the normal cutover profile. Using regressions of soil depth on total soil N it was calculated that c. 2.5 and 26 cm of soil had been scalped off the inter-windrow and skid sites respectively.

Relationships between phosphate retention and Bray (0.1M HC1 + 0.03M NH₄F) extractable aluminium, iron and calcium were examined in the topsoils of 128 forest soils collected from throughout New Zealand.

Aluminium extracted using 1- and 30-minute extraction periods was highly significantly correlated with P retention (r = 0.882 and 0.920 respectively). Iron and Ca in the same extracts were closely related to P retention only within a few specific soil groups and not over all soils. Other soil properties commonly used to characterise forest soils; carbon, cation exchange capacity, pH and total P, were also significantly correlated with P retention over all soils. However the correlation coefficients were smaller than those from Bray extractable Al and stepwise regression procedures indicated their effects were predominantly indirect through association with extractable Al.

In the interest of efficient fertiliser use, critical levels of Bray 2 (1-minute extraction) extractable Al below or above which water-soluble fertilisers should not be used on forest soils are tentatively proposed.

Using nitrogen fertilisers on Pinus radiata grafts and cuttings, substantial increases were made in the concentrations of free arginine in buds with a potential for cone production.

The increases, when promoted in seed orchards, did not lead to increased cone production.

It is suggested that the major role of N, where this has increased cone production in Pinus, may have been to increase crown size and thus the number of sites in the crown where cones may be initiated. This would only happen on sites where growth rate and crown size were limited by the availability of N.

Two experiments investigating the effect of clearfelling on decomposition of Pinus radiata D.Don litter are described. The first was a field trial in which P. radiata trees were felled without disturbance to the litter layer. Small plots were laid out in the clearfelled area and in an adjacent closed-canopy stand. Screens of shade cloth were erected over the plots. Of the litter originally present Degree of shading had no effect on litter decomposition. In the second experiment, cuttings of P. radiata were planted in troughs designed to expose weighed experimental litter to the influence of plant roots but not to the influence of plant tops. Shades were placed over the trough surfaces and the plants grown until mycelial wefts were visible in the litter. Twenty-four troughs were then selected and plants in 12 of them were severed at litter level. Six troughs containing a growing plant and six with a "felled" plant were placed in a growth room simulating the climate of an open, clearfelled area. A similar set was placed in another room simulating the climate under a closed-canopy pine stand. Shades were removed from the troughs in the "open" climate room. All troughs were watered to field capacity daily. After 6 months, significantly more litter remained in the troughs with intact plants than in those where the plants had been "felled", irrespective of whether they were in the "open" or in the "forest" climate room. The first experiment suggested and the second experiment confirmed that the biological changes resulting from clearfelling, including the removal of mycorrhizal root influence, were more important in increasing litter decomposition than the physical effect of the change in climate.

A study of regeneration of rimu following selection logging of terrace rimu forest showed best recruitment on sites which had moderate to severe soil disturbance. Dense fern and hardwood regrowth limited both rimu regeneration and growth rates after 4 years. Average growth rates of seedlings established early after logging was 6 cm/annum.

The effect on water quality of urea and superphosphate aerial topdressings of Pinus radiata stands was studied at five sites. Urea was applied at a rate of 500 kg/ha to 126 ha of the Mangotutu catchment near Kinleith. A total net loss of 95 kg N (0.33% of applied N) occurred during a 21 week period after aerial topdressing. Of this amount, 46.0 kg was lost during the first week by direct fall into the stream. Nitrate N reached a maximum of 1.18 mg/1 some 44 days after application. A 73 ha catchment in Golden Downs S.F. received 540 kg/ha of superphosphate. Over a 189 day period only 1.2 kg of elemental P (less than 0.01% of that applied) left the catchment. The P0₄-P level peaked at .109 mg/l shortly after topdressing and was back to normal within several days. Two catchments in Tasman Forest, west of Nelson, received 200 kg/ha of urea and 400 kg/ha of superphosphate. The smaller (74 ha) catchment was entirely topdressed and exhibited much higher levels of N and P in streamflow (1.72 mg/1 total P and 0.79 mg/1 total N). The larger (478 ha) catchment received fertiliser on only 199 ha and its stream was not overflown. Total P and total N levels reached maxima of only 0.031 mg/1 and 0.72 mg/1 respectively. An 18 ha catchment in Tairua S.F. was topdressed with 1250 kg/ha of superphosphate. Despite a very high rise in P0₄-P concentration in streamflow to 51.87 mg/1, total loss of P was only about 0.06% of that applied. A similar amount of superphosphate applied to a 31 ha catchment in Riverhead S.F. produced a maximum stream concentration of 16.13 mg/1 P0₄-P. Inputs of forest fertilisers can be kept low by using 20-m buffer strips along stream edges, topdressing during no-wind conditions, and using larger granule fertilisers dropped from low altitudes.

It is essential to define the objectives of an investigation carefully at the outset, to delineate management units and biologically different populations within it, and finally to provide response information in a form that allows forest managers to forecast long-term yields. For most trials other than preliminary investigations factorial layouts of simple balanced designs are advocated, as is partial confounding in incomplete blocks or completely randomised single-tree plots. Soil and foliar analyses are considered to be useful aids for delineating populations and choosing fertiliser treatments. In turn, results from fertiliser trials can be used for refining the calibration of these diagnostic methods. Measurements taken should be appropriate to the aims of the experiment and to the variability among and within trees. Intensive measurement of a small representative sample is preferred to coarse measurement or indirect estimation of many individuals. Precautions to be taken in checking the apparent reliability of individual measurements and in adopting appropriate statistical techniques to avoid misleading results are briefly discussed.

Several silvicultural aspects of forest fertilisation other than volume responses, are reviewed with respect to the present New Zealand situation.

Fertilisation to increase flowering in New Zealand seed orchards has not been successful. However, continued use at reduced levels may be justified in terms of orchard health and vigour.

Substantial increases in tree form factor can occur in Pinus radiata following N fertilisation and thinning. These increases are correlated with crown growth pattern.

Increased crown growth rates in fertilised, thinned stands suggest optimal thinning regimes will be different for fertilised stands.

Fertilisation at establishment increases the probability of frost damage.

Weed control should accompany fertilisation at establishment for best, most reliable, results.

Wood density is generally reduced by fertilisation but is more than compensated for by increased volume growth. Density reductions measured at 1.4 m may overestimate the importance of such reductions.

Fertilisation has been shown to influence susceptibility to insects and disease in several overseas countries. In New Zealand, such effects have not been demonstrated.

Only limited information is available in New Zealand on the effect of intensified forest management practices on nutrient status and potential fertiliser requirements of Pinus radiata forests. Projections must therefore use the substantial overseas literature.

Projections are made of nutrient depletion under a variety of management practices, such as waste and commercial thinnings, in addition to the final harvest. Owing to the limitations imposed by the information available, only provisional conclusions could be drawn. However, intensification in management through shorter rotations, closer utilisation, slash burning and windrowing must greatly increase nutrient removal particularly when two or more of these practices are used in conjunction. Other features of intensive management, such as thinning, clearfelling per se, and bedding in site preparation, have much smaller effects. Referring to nitrogen specifically, sufficient reserves and inputs are generally available for the next crop at present but, with intensified management, productivity will only be maintained through substantial fertilisation.

Residual benefits of P fertiliser applied during the previous rotation were evaluated on a severely P-deficient soil in Riverhead Forest. Plots treated with 225 kg/ha P 19 years previously and their controls were subdivided at establishment of the second Pinus radiata crop. Half of each main plot received a standard establishment application of P fertiliser (17 g/seedling P) and the other half was left untreated.

Five years after establishment trees in all sub-plots which had received any fertiliser had gained at least a year's growth advantage over those which had received no fertiliser. Growth of trees in sub-plots which received a single P application in either the first or second rotation was similar and slightly greater than that of trees in sub-plots which received both applications. This slight suppression was attributed to the second P application accentuating a N deficiency induced in the old +P plots by the growth response of the first rotation crop.

Analysis of both foliage samples collected from old crop trees prior to felling and soil samples collected prior to re-establishment provided a good index of the residual effectiveness of the previous fertiliser application.

Investigations into and use of phosphate fertilisers on impoverished soils in Auckland Conservancy started in the 1950s and routine aerial applications of superphosphate are now accepted as standard management practice in both Auckland and Nelson Conservancies. Foliar analysis is used to monitor the crop P status and superphosphate is applied to keep foliar P levels above 0.12% dry weight. The usual application rate is between 55 and 110 kg/ha P and on poorer sites several dressings are required during the first rotation. Fertiliser trials and other studies have provided a good basis for these practices and correction of acute P-deficiency by applying high rates of P often results in volume responses of about 30 m³/ha/year.

Nitrogenous fertilisers applied at about 200 kg/ha N will increase productivity on many sites. At mid-rotation on fertile Central North Island soils, volume responses often exceed 8m³/ha/year; on more infertile sites in the Nelson region responses to N + P fertiliser are about 17 m³/ha/year. However, on the infertile soils responses to N have usually been short-lived (4-5 years). Best responses have been obtained where applications are made within 2 years of thinning. Foliar analysis is currently an unsatisfactory basis for recommending N prescriptions, Lupinus arboreus has been effective in improving the N economy of forests planted on coastal sands.

Boron and copper fertilisers are required on some sites to prevent malformation of trees. The use of boron fertilisers, applied at between 4 and 12 kg/ha B, is a common practice in several South Island forests. Copper deficiency occurring in limited areas of sand dune forests in Northland is corrected by the application of 5 kg/ha Cu. Foliage analysis and the appearance of symptoms are the main diagnostic techniques used in deciding where and when to apply these two micronutrients.

Deficiencies of potassium and magnesium occur only to a limited extent and are of little practical significance. The main areas of K deficiency are on soils derived from ultrabasic rocks. Magnesium deficiency has been found on the yellow-brown pumice soils of Rotorua Conservancy, on soils derived from the Moutere gravels in Nelson Conservancy and on certain gley-podzols in Westland Conservancy.

This paper reviews New Zealand research and experience with fertilisers at establishment of plantations of exotic tree species and outlines current management practice.

The first commercial use of fertilisers at establishment was made in the mid-1960s during planting of radiata pine on P-deficient clay soils. Currently c. 6000 ha of new plantings are fertilised annually. The main fertiliser elements are P, N and B. All are applied manually on an individual basis in order to minimise stimulation of competing vegetation. The most common practice is to place the fertiliser in a spade slit some 15 cm from the base of the seedling within 3 to 8 weeks after planting.

Phosphorus is applied to radiata pine at establishment mainly on weathered and leached clays and podsolised sands in the Auckland region and on strongly leached alluvial gravels in the Nelson region. With minor variations application rates are (as P) 17 g/seedling in the Auckland region and 6-10 g/seedling in the Nelson region. Most P is applied as superphosphate (8-10% P). Responses to P tend to be enhanced by site preparation methods involving weed control and deep soil cultivation. Spot applications of P at establishment are usually effective for only 3 to 4 years.

Nitrogen is applied at establishment of radiata pine on podsolised soils, skid sites where topsoil has been removed and on strongly leached alluvial gravels. The most common application rate is c. 15 g/seedling of N applied as urea, or diammonium phosphate where both N and P are required. Nitrogen is used in the establishment of Eucalyptus spp. on a range of sites with up to 30 g/seedling of N (as urea) being used. Establishment applications of N tend to be effective for only 1 to 2 years.

Boron is used to a limited extent in the establishment of radiata pine on strongly leached soils formed from alluvial gravels and granite in the Nelson region. It is usually applied in the form of boronated superphosphate to give 0.8 g/seedling of B. These applications are usually effective for only 3 to 4 years.

Representative samples of Pinus radiata planting stock (1/0, 1.5/0 or 2/0) were collected at time of lifting from 17 nurseries throughout New Zealand. Individual sample averages for size, dry weight and nutrient content ranged widely for each age-class as a result of differences in seed source, climate, soil type and management practices. For 1/0 and 1.5/0 stock, mean seedling height was 23-44 cm and 33-60 cm respectively, while average dry weight per seedling for the same two age-classes was 6.3-15.1 and 14.7-32.5. Nutrient removal by crops also ranged widely. The highest dry matter production for

1/0 crops was 7.9 t/ha at a stocking of 525 000 seedlings/ha. This crop contained (kg/ha): 76 (N), 9 (P), 49 (K), 4 (Mg), 30 (Ca), 0.08 (B), 2.9 (Mn) and 0.3 (Zn). The highest dry matter production recorded for the 1.5/0 crops was 20 t/ha at a stocking of 616 000 seedlings/ha. For this crop, nutrient removal was equivalent to (kg/ha): 232 (N), 32 (P), 140 (K), 14 (Mg), 57 (Ca), 0.23 (B), 3.4 (Mn) and 1.4 (Zn).

Commercial fertilisers provide a convenient and effective means of maintaining a satisfactory level of balanced nutrition in nurseries provided they are used with proper regard to timing and in quantities which have some relation to the actual requirements. For many years their regular use has been regarded as an accepted part of nursery husbandry. In New Zealand Forest Service nurseries, as well as some private forest nurseries, assessment of requirements is made largely on the basis of standardised agricultural soil tests. Soil sampling methods and interpretation of soil test results are outlined. Prescriptions based on soil test ratings have generally helped to maintain satisfactory growth in successive crops, while preventing cumulative excesses which could also adversely affect nursery stock.

Fertilisers are commonly applied during bed preparation (especially P, K and secondary nutrients (Ca, Mg, S) as low-cost simple agricultural fertilisers), as well as later during the period when seedlings are making rapid growth (light maintenance side- or topdressings of granulated multinutrient fertilisers or nitrogenous fertilisers according to soil requirements).

In the event of poor growth or malnutrition symptoms affecting a crop, visual diagnosis, aided where necessary by foliar analysis, is used to resolve the cause so that prompt remedial action can be taken, e.g., by foliar spray. Descriptions of diagnostic symptoms and "critical" foliar nutrient levels for radiata pine seedlings are given.

In 1975, 15 915 ha of forests were fertilised during routine management operations. Of this 4 617 ha were newly planted land, 7 875 ha were in established stands of exotic species, 2 852 ha were in protection forestry zones and 571 ha were in nurseries and seed orchards. Between 1954 and 1976, 54 529 ha of production forests were fertilised, over 90% of which was in Pinus radiata.

Quantities of N, P, K, Mg and B used in 1975 were 560, 515, 36, 22 and 28 tonnes respectively. Most of the N, P and B was applied to production forests while most of the K and Mg was used in nurseries. The principal fertiliser sources of N, P, K, Mg and B were urea, superphosphate, NPK compound fertilisers, dolomite and dehydrated sodium borates respectively.

Based on an assumption of fertiliser use on all responsive sites, forestry use in 1985 was projected to be (tonnes):

N 14,000

P 3,000

K 70

Mg 30

B 130

Deficiencies of N, P, K, Ca, Mg, B, Cu, Zn, and Fe have been found in nurseries and/or plantations of Pinus radiata in New Zealand. The visual symptoms are described and details of the soil types on which they occur are given. Deficiency-like symptoms due to other causes are described. While visual symptoms give an immediate and usually reliable indication of the presence of a nutrient deficiency, confirmation by foliage analysis is recommended. Deficiency foliage levels of each nutrient are given.