The paper which this Corrigendum refers to is available here: Empirical models evaluated for prediction of fine fuel moisture in Australian Pinus radiata plantations

The influence of four tree species (Picea abies, Abies alba, A. grandis and Larix leptolepis) on calcium, magnesium, and potassium ecosystem budgets at the Susegarden site in south-western Sweden were evaluated. Data on nutrient contents in biomass and soil were obtained from a study in a 32-year-old tree species experiment at Susegarden. Deposition levels for the 32 years were calculated from data obtained at nearby monitoring stations, and weathering rates were calculated using the PROFILE model. For calcium and potassium, lower rates of nutrient uptake by L. leptolepis and A. alba than by P. abies and A. grandis had been followed by increased leaching, thus resulting in export of a major portion of nutrients not taken up. Species-related differences in soil pools of organically bound and exchangeable calcium and potassium could be offset if stems only were harvested or if whole-tree harvest were to be combined with ash recycling. For magnesium, the differences in nutrient uptake among the tree species were relatively small. Still, there had been a higher relative build-up of the soil pool of magnesium in L. leptolepis than in the other species, which implies there had been less leaching. For all species, it is likely that the sum of exchangeable and organically bound calcium and potassium in the soil had decreased over the 32-year period.<

Starting in 1989, a series of lysimeter studies was initiated to evaluate the potential impacts of different harvesting and site preparation methods on site quality. Experiments were laid out in the field on soil types representative of the land base supporting the growth of all the major commercially important tree species in the Maritimes region (New Brunswick, Prince Edward Island, Nova Scotia). Although different treatments applicable to local situations were implemented on each site, three treatments included on all sites were: (1) control (no harvest); (2) conventional stem harvest (stems only) with slash left on site; and (3) whole-tree harvest (all biomass above the stump removed from the site). On all study sites, soil temperature was monitored hourly at 3 points: (i) immediately below the organic horizons; (ii) mid-way between the surface and the bottom of the rooting zone; and (iii) below the rooting zone. Hourly mean temperatures in the top (immediately below the organic) horizon clearly exhibited effects of harvesting methods. In the whole-tree harvest plots, during June-August, the hourly mean temperature was 6-8 deg C warmer than that in the conventional harvest plots. Also, temperature peaked about 2 h later in the whole-tree harvest plots than in the conventional-harvest plots. Similar trends were consistently recognisable at lower depths as well, indicating that whole-tree harvesting has the potential to enhance weathering in the subsoil. The treatment effects were equally distinguishable in the values for daily mean temperature, except in the early spring and later summer (late August) when the daily mean temperature was higher in the conventional-harvest plots than in the whole-tree harvest areas owing to the insulating effect of slash. The accumulated heat units (cumulative number of hours times the soil temperature above 5 deg C) were greatest in the whole-tree harvest areas, followed by the conventional-harvest and then the control plots.

The mechanisms by which whole-tree harvesting affect growth of second-rotation Sitka spruce (Picea sitchensis) were studied for 2 years on a stagnohumic gley soil in Kielder Forest, Northumberland, UK. The full factorial experiment included treatments with harvest residues ( plus or minus R), fertilizer additions ( plus or minus F), and herbicide ( plus or minus H), giving a total of eight treatments in three replicate blocks. Fertilizer and herbicide treatments increased foliage nutrient concentrations which were above those expected to limit growth of young Sitka spruce. The removal of harvest residues decreased height growth in both years (p<

Nutrient accumulation and partitioning by second-rotation Pinus radiata and ecosystem recovery from intensive harvesting, residue management, and urea fertilization were evaluated 5 years after trial establishment in a sand dune forest in New Zealand. Experimental treatments applied in a split-plot design included: whole-tree harvest and forest floor removal; whole-tree harvest; stem-only harvest; and stem-only harvest plus addition of extra slash. Urea was added quarterly to sub-plots at a rate of 200 kg N/ha each year. Forest floor removal substantially reduced stand productivity, and indicated the importance of organic matter as a store of nitrogen on the Pinaki sands. All stands without fertilizer continued to lose nitrogen over the 5-year period after trial establishment, and retained between 73% and 88% of the nitrogen left on site. Stands with fertilizer retained between 63% and 81% of the nitrogen added over the 5-year period. Slash increased ecosystem nitrogen retention. Stands treated with stem-only harvest plus extra slash and fertilizer accumulated nitrogen to pre-harvest ecosystem content, while those with other treatments did not. Urea additions amended productivity losses due to forest floor removal; however, fertilizer increased nutrient accumulation rates for elements not added to the site, and exacerbated reductions in nutrient availability caused by harvest treatments. Productivity to nutrient accumulation ratio (P/NA) of nitrogen was greater on the sand dune site (0.27 t/kg N) than observed at Purukohukohu Experimental Basin on a nitrogen-rich loamy pumice soil (0.16 tonne/kg N) in New Zealand. These differences suggest the need to revise critical levels for foliar nutrients based on site-specific P/NA values. Urea fertilizer generally increased P/NA for phosphorus and potassium, and reduced P/NA of nitrogen, calcium, magnesium. In stands with and without added fertilizer, P/NA for boron was lower in stands with slash retained than in stands with forest floor removal or whole-tree harvesting. In stands with forest floor removal, addition of urea increased the P/NA ratio for boron. It is hypothesized that forest floor removal reduced the ability of the soil to satisfy tree demand for boron, especially for fast-growing fertilizer-treated trees.

The prospects for managing nitrogen in established Pinus radiata plantations growing on sandy soils in southern Australia, is discussed, using results from a long-term project initiated in 1988 in South Australia as an illustration. Nitrogen uptake can be manipulated through thinning, management of residue, and fertilizer use. Thinning, in the absence of above-ground residue, results in a small increase in nitrogen uptake per hectare, but can more than double nitrogen uptake per tree. This reflects the capacity of the thinned stand to take up all mineralized nitrogen. Thinning contrasts with clear-felling which results in substantially increased soil mineral nitrogen concentrations and leaching. Uptake of nitrogen after thinning increases with the quantity of residue retained; all this nitrogen is taken up, and there is no leaching. The release of nitrogen from residue is progressive and reflected in the pattern of nitrogen uptake. In contrast, fertilizer results in a rapid, large, but ephemeral increase in nitrogen uptake which is associated with increased soil mineral nitrogen concentrations and high leaching losses. Patterns of nitrogen uptake after fertilizer application, and simple models of nitrogen leaching and uptake, indicate there is scope for improving the effectiveness of fertilizer use by varying the timing of application with respect to season and thinning schedule. There is probably little scope for influencing nitrogen uptake in established stands by varying the form of nitrogen fertilizer applied or through the use of nitrogen-fixing associations.

A mature ponderosa pine (Pinus ponderosa) forest located on the eastern slopes of the Cascade Mountains, Washington, was treated with 3 different nitrogen fertilizers (urea, ammonium nitrate and a domestic sewage sludge) to compare their relative ability to increase extractable soil-N, pine foliar-N and basal area. Urea and ammonium nitrate were applied at a rate of 220 kg N/ha, and sewage sludge at 11 t/ha (which was assumed to provide 240 kg available-N/ha in the first year). All fertilizers increased extractable soil-N in the first year after application, but not always significantly; levels decreased to those of the control soil by year 2. Foliar concentration of N was increased by all fertilizers; however, urea did not increase foliar concentrations until the second year after application. Sewage sludge continued to increase foliar-N through year 5, and caused the highest levels of foliar-N. Basal area was not increased by any fertilizer over the 5-year period. Soil solutions showed increases in ammonium (NH₄⁺) and nitrate (NO₃^-) in the upper profile, but increases in solution N at the base of the soil profile were found only with the urea treatment.

An overview is presented of several previously published studies, mostly in French, concerning the effects of phosphorus nutrition on copper movements through the soil/micro-organism/plant system by endogenous and extraneous regulation. All experiments involved maritime pine (Pinus pinaster) growing on the typical sandy soil (hydromorphic humic podzol) representative of nearly 60% of the pine plantation in Landes de Gascogne, France. Phosphate fertilizer affects copper solubility in the soil chemically, by soil micro-organism changes, or by root modification, and it also affects copper uptake and translocation from root to shoot, including xylem sap chemistry in field-grown trees. The level of copper nutrition is important and understanding of the physiological interaction has practical consequences for pine fertilizer treatment and copper deficiency monitoring.

Soils, climate, and historical factors affecting plantation distribution, and attitudes toward nutritional management, have affected the use of fertilizer in Australian plantations, primarily exotic pines (Pinus spp.). The diverse nature of nutritional problems encountered in plantations across Australia, and the separate management agencies involved, resulted in a strong divergence of policies and practices regarding the use of fertilizers among the different States until the 1980s. At this time various common pressures, including increasing land costs, prompted reconsideration of productivity gains and returns on investments. As a result there have been several important changes in approaches to nutritional management: nutrition is now regarded as one component of total crop management; plantations are managed on a site-specific basis; management tends to be more intensive, with increased productivity per hectare; soil moisture and nutrients are managed more efficiently; and genetic improvements in nutrition and other parameters are being sought to increase performance, health, and tree form. Nevertheless, actual fertilizer practices vary considerably among regions owing to vast differences in soil and climatic conditions. Fertilizer practices in eucalypt (Eucalyptus spp.) plantations are still being developed although there is considerable information transfer from experience gained with exotic pines.

Knowledge of simple nutrient cycles (phosphorus, potassium, sulfur) in grazed pastures, and of the influences of soil, climate, topography, and management on gains and losses of nutrients from the cycles, is used to estimate maintenance fertilizer requirements for New Zealand farmers. The principles involved in applying theory to practical management should be applicable to long-term plant production systems other than pastures.

Nutrient uptake and growth of rapidly expanding needles in the upper crown of Pinus radiata were studied in a 3x2 factorial experiment in relation to competition with pasture for nitrogen and soil moisture. The monthly addition of 30 kg N/ha had little effect on needle growth or nutrient uptake and the effect of simulated grazing was intermediate to either the rank-pasture or the no-pasture treatment. Pasture competition decreased maximum rates of needle growth and nitrogen, calcium, and magnesium uptake; needle mass; and needle nitrogen, potassium, calcium, and magnesium content. In the presence of pasture, needle growth and uptake of potassium and magnesium declined more rapidly. Maximum needle weight and potassium content were also achieved earlier when pasture was present. Gompertz equations proved to be a useful technique for modelling nutrient uptake and making comparisons between treatments, particularly those that affected the dynamics of nutrient uptake, i.e., nutrient sources and addition rates, competition, species, and genotype.

Phosphorus cycling through various soil pools of a podsol was measured at 2 Pinus radiata fertilizer trial sites in New Zealand. Tree growth rates differed markedly between sites, but the growth response to phosphorus treatment was absent at one site and small at the other. The surface mineral soil horizons were mainly quartz sand, and the 0-15 cm layer of the soils contained very little inorganic phosphorus compared with organic phosphorus. The phosphorus in most pools increased with higher rates of phosphorus fertilizer. There was no significant increase in tree growth, litterfall, soil carbon, or microbial carbon pools, and thus the P/C ratios of soil pools generally increased. The phosphorus mineralization rate also increased with phosphorus treatment. The microbial biomass phosphorus made up a large proportion of the forest floor phosphorus, and the solution phase in the forest floor contained large concentrations of inorganic phosphorus that probably arose from mineralization of organic matter during turnover of the microbial biomass, together with direct leaching from needles. The concentration of inorganic phosphorus in the soil solution of the mineral soil was less than in the forest floor. Since there was little phosphorus sorption by the mineral soil, uptake of phosphorus by the trees directly from the forest floor would account for the observed drop in inorganic phosphorus. Uptake of phosphorus by the trees was highly correlated with microbial phosphorus. There appeared to have been losses of phosphorus from the ecosystem, and leaching of phosphorus had probably occurred to at least the base of the E horizon. At the higher rate of phosphorus fertilizer, microfauna feeding on micro-organisms in the forest floor had a similar biomass to those at the lower rate of phosphorus but there were larger numbers of smaller microfaunal organisms. This suggested that there may have been shorter generation times, more microbial grazing, and enhanced nutrient cycling as a result of the improved phosphorus status of the substrates. The overall phosphorus cycling rate also probably increased with a higher rate of applied phosphorus.

The effects of microbial energy supply and low-level nitrogen fertilizer treatment on microbial respiration, nitrogen mineralisation, and tree foliar chemistry were addressed through field manipulations and modelling analysis. Sugar, sawdust, and nitrogen fertilizer were added to a series of upland successional communities in interior Alaska. Forest floor respiration and tree foliage chemistry were measured the year prior to treatment and for 2 years after treatment. LINKAGES and CENTURY were used in an attempt to duplicate the short-term field measurements and to extend the predicted effects to a longer time period. Ecosystem structure and function simulated by both models were consistent with field measurements of upland hardwood (dominated by Populus tremuloides, P. balsamifera and Betula papyrifera) and mature Picea glauca control stands. Neither model accurately predicted the effects of large-scale disturbance to the treated sites.

Uptake kinetic parameters for forest species are required in nutrient uptake models in order to accurately predict nutrient uptake by root systems. Several techniques have been used to calculate the kinetic parameters from depletion experiments. The objectives of this study were: (1) to investigate four methods (Observed, Polynomial, Bhat, and Claassen and Barber) for determining Michaelis-Menten kinetics for potassium uptake by slash pine (Pinus elliottii var. elliottii) seedlings; and (2) to determine the implications of using the values derived by the four methods on predicted potassium uptake using a nutrient uptake model. The four methods resulted in similar estimates for the kinetic parameters Imax and Km; however, partial depletion curves gave unreasonable estimates of Imax and Km using the observed and polynomial methods. Curve-fitting programs were useful in smoothing the data in order to calculate the kinetic parameters. Simulations of potassium uptake were also similar between each method except for the kinetic parameters from the partial depletion curves, suggesting that depletion curves should approach some low concentration in order to properly calculate Imax and Km parameters.

Quantitative mechanistic models, such as NUTRIENT UPTAKE, are useful tools in refining our understanding of the chemical, physical, and biological complex that controls plant nutrition. Previous work with woody species has raised important issues on how best to derive model input values and to set parameters on the model, given that many of these values change substantially over even one growing season. Data for this analysis were obtained by growing loblolly pine (Pinus taeda L.) seedlings from two families from seed in pots containing soil which had been amended with potassium, phosphorus+potassium, nitrogen+potassium, and nitrogen+phosphorus+potassium at rates equivalent to 67 kg K/ha, 28 kg P/ha, and 196 kg N/ha. Seedlings were harvested after each foliar growth flush over the course of one growing season, and information was collected on root growth and soil supply parameters. Solution depletion techniques were used to establish potassium and ammonium uptake kinetics values for both families. These data were then used to set parameters for the NUTRIENT UPTAKE model. Results indicate that such models should use values for root morphological characteri sties that are more reflective of the seasonal average. Changes in soil supply parameters will need to be taken into consideration and, again, seasonal means appear more appropriate. Comparisons of model predictions with observed plant uptake of potassium and nitrogen indicated substantial over-estimates of uptake (1.1 to 10.0 times observed) by the model. Based on model runs and previous experience, this over-estimate was judged to be largely a function of the magnitude of the experimentally derived I_max value. As an alternative, the model can be used to calculate theoretical I_max values based on observed uptake in order to approximate growth interval or annual uptake more closely.

Quantitative mechanistic models, such as NUTRIENT UPTAKE, are useful tools in refining our understanding of the chemical, physical, and biological complex that controls plant nutrition. Previous work with woody species has raised important issues on how best to derive model input values and to set parameters on the model, given that many of these values change substantially over even one growing season. Data for this analysis were obtained by growing loblolly pine (Pinus taeda L.) seedlings from two families from seed in pots containing soil which had been amended with potassium, phosphorus+potassium, nitrogen+potassium, and nitrogen+phosphorus+potassium at rates equivalent to 67 kg K/ha, 28 kg P/ha, and 196 kg N/ha. Seedlings were harvested after each foliar growth flush over the course of one growing season, and information was collected on root growth and soil supply parameters. Solution depletion techniques were used to establish potassium and ammonium uptake kinetics values for both families. These data were then used to set parameters for the NUTRIENT UPTAKE model. Results indicate that such models should use values for root morphological characteri sties that are more reflective of the seasonal average. Changes in soil supply parameters will need to be taken into consideration and, again, seasonal means appear more appropriate. Comparisons of model predictions with observed plant uptake of potassium and nitrogen indicated substantial over-estimates of uptake (1.1 to 10.0 times observed) by the model. Based on model runs and previous experience, this over-estimate was judged to be largely a function of the magnitude of the experimentally derived I_max value. As an alternative, the model can be used to calculate theoretical I_max values based on observed uptake in order to approximate growth interval or annual uptake more closely.

The fine-root system of perennial, dicotyledonous woody species can be dominated by brown roots. Although as much as 90% of the surface area of a root system can be in this category of roots, the nutrient uptake characteristics of brown roots are not well understood. If this part of the root system has active uptake, then its significance is obvious. If it does not then modelling predictions of nutrient uptake will need to account for this non-functional segment of the measured root system. The topic of nutrient management strategies in forest systems is crucial to the understanding and predictive modelling of soil nutrient availability to species with these root characteristics.

The effect of age on forest nutrition was examined from sequential observations over 25 years in a natural jack pine (Pinus banksiana) stand on glacio-fluvial soil in the boreal forest of northern Ontario, Canada. Comparisons of indicators of nutrition were made between this stand and other mature jack pine stands of lower site productivity in Ontario, New Brunswick, and Wisconsin. Greater phytomass and nutrient contents were associated with older stands of higher site productivity. Nutrient-use efficiency by jack pine varied with age and decreased with increasing site fertility. Jack pine net uptake of nitrogen and phosphorus increased from 16.5 and 2.6 kg/ha/year at site index (SI) 11.4, to 44.2 and 4.4 at SI 19.0. On less fertile, lower productivity sites, the proportion of the stand net uptake of nitrogen and phosphorus supplied by retranslocation did not increase. Retranslocation of nitrogen and phosphorus increased with increasing foliar phytomass and canopy nitrogen and phosphorus contents. There was a reduction in accumulation of phosphorus in the juvenile closed forest and potassium at the approach of maturity in the pine stand with the best nitrogen nutrition.

All species of trees share the same basic nutrient requirements. Proportions of mineral nutrients needed for unimpaired growth are similar among woody and herbaceous plants (at least under controlled laboratory conditions), although the quantities required per unit of time differ according to inherited potentials for growth. Availability of mineral elements has a large impact on dry matter partitioning between plant parts. Root growth can be favoured as well as suppressed in response to low nutrient availability. Both conifers and broadleaved species (deciduous and evergreen) can be very fast-growing under favourable soil conditions. Generally, conifers and broadleaved evergreens use less NPP (net primary productivity) for foliage production than deciduous species but the quantity of nutrients taken up and returned annually to the forest floor is generally lower in evergreen species. Nutrient-use efficiency, particularly of nitrogen, is slightly higher in conifers than in deciduous broadleaved species; it becomes higher when trees grow older and the processes associated with internal nutrient cycling are operating fully. Plantations managed for short rotations are the most nutrient-demanding, and cause the greatest losses of nutrients from the site at harvest<

Preliminary tests on small pieces of veneer under room conditions were used to determine the tensile strength of Pinus radiata D.Don perpendicular to the grain in the radial direction. These tests were undertaken to provide failure information for devising loading tests at elevated temperatures with veneer sheets. The use of veneer has attractions in that, firstly, replication of samples is simple as the properties of flat-sliced veneer change relatively slowly along a veneer sheet or between adjacent veneers and, secondly, the loads at failure are relatively small, so making any test apparatus comparatively simple in construction.

A simplified description of drying kinetics was obtained from a rigorous mathematical model to describe the drying behaviour of a Pinus radiata board under high temperatures. Simplified characteristic drying curves, covering the falling rate drying periods, were coupled with mass and heat balances over a control volume to determine the changes in air conditions (humidity and temperature) and local average moisture content through the stack. This kiln-wide model was solved numerically to calculate the influence of airflow reversals under different strategies. In drying of a kiln stack of sapwood boards with unidirectional airflow, the maximum difference in local average moisture content was about 0.4 kg/kg between 6 and 16 hours from the start of drying. Reversing the airflow every 4 or 8 hours only reduced the period in which the maximum difference in moisture content persisted, but no decrease in the greatest difference is predicted. This peak difference could be reduced to 0.3 kg/kg with airflow reversals every 3 hours. If the airflow was first reversed after 2 hours and again after 6 hours from the start of drying, the greatest difference in moisture content could be restricted to a little over 0.2 kg/kg. However, after 12 hours of drying, the various reversal strategies produced essentially similar profiles of moisture content, with differences across the kiln between 0.1 to 0.2 kg/kg. In the drying of heartwood, differences were smaller, the maximum difference in local average moisture content being less than 0.07 kg/kg with unidirectional airflow. This small difference could be reduced to less than 0.04 kg/kg when the first airflow reversal was performed within 4 hours of the start of drying.

Predictions of local temperature and moisture content profiles in the high temperature drying of single Pinus radiata boards of 100x50 mm, for both unidirectional flow of air and airflow reversals, were based on a rigorous mathematical model. This was reviewed and confirmed in drying tests conducted at New Zealand Forest Research Institute (NZFRI). When the air flowed in one direction only, temperatures were higher and moisture contents were lower near the leading edge of the board than at other positions across the board, because of the decrease in heat and mass transfer coefficients with distance from the leading edge. These differences could be reduced to a certain extent, by reversing the airflow, thus establishing more uniform temperature and moisture content profiles. In the drying of a sapwood board using unidirectional airflow at dry bulb/wet bulb temperatures of 120 deg /70 deg C, the maximum moisture content variation between the leading and trailing edges after four hours of drying was predicted to be 27%. This variation persisted for about 6 to 8 hours, before decreasing with further drying. The largest difference in surface temperature (27 deg C) occurred between the same positions as for the moisture content after 6 hours of drying. With airflow reversals, the differences both in temperature and in moisture content were reduced, with the middle region becoming the wettest during drying. Airflow reversals every 4 to 8 hours shortened the period of maximum moisture content difference, but the peak value was not reduced. Reversing the airflow every 3 hours, or reversals after 2 and 6 hours, was more effective in reducing the greatest moisture content difference to below 20%. All reversal strategies resulted in similar moisture content and temperature profiles in the later period of drying (after 16 hours). For heartwood, the benefit of airflow reversals was not as significant as that for sapwood, since the differences in both temperature and moisture content with unidirectional airflow are smaller because of the much lower initial moisture content of heartwood.<

Inoculations were made into host trees using normal and degenerate strains of Seiridium unicorne (Cooke & Ellis) Sutton. Pathogenicity tests on rooted cuttings under glasshouse conditions showed very significant differences in pathogenicity between normal and degenerate strains. Pure normal strains were most virulent, degenerate isolates were completely impotent, while simultaneous inoculations with both types produced lesions 58-72% shorter than those with normal cultures, with a corresponding 64% reduction in associated resin bleeding and crown dieback.

Seiridium unicorne (Cooke & Ellis) Sutton and S. cardinale (Wagener) Sutton & Gibson, the causal agents of cypress canker, gain entry through cracks in the bark or through wounds (Birch 1933; Fuller & Newhook 1954). Pruning of cypresses is a common practice in New Zealand and the work described in this Note was carried out to see whether pruning led to an increase in incidence and severity of cypress canker.<

Neurospora intermedia Tai and its Chrysonilia von Arx anamorph are reported from debarked Pinus radiata D. Don logs. Species of Neurospora forming a surface mould on timber appear to have a wide geographic distribution and do not represent a threat to the soundness of timber.

Diplodia taxi (Sowerby) de Notaris occurring on Taxus baccata Linaeus is reported as a new fungal record for New Zealand.

Decline of Lupinus arboreus Sims in the Pinus radiata D. Don forests established on New Zealand's west coast sand dunes was first recognised in late 1988. Lupinus arboreus had played an important dual role in the sand dune forests, providing the shelter necessary for establishment of the young pine trees on the windswept sites and also supplying nitrogen to the ecosystem, thus decreasing the need for applications of artificial nitrogenous fertilisers. Colletotrichum gloeosporioides (Penzig) Penzig & Saccardo, previously unrecorded on L. aboreus in New Zealand, was found to cause rapid mortality of seedlings, and dieback and stem cankering of older plants. A 4-year programme monitoring the effect of the disease on lupin populations has demonstrated that both longevity of plants and production of seed have been reduced since the blight was first recognised. Lupin seed was shown to be a source of infection.

Upper Mid-Crown Yellowing (UMCY), needle retention, and foliar chemistry were determined for Pinus radiata D.Don clones at the Kaingaroa Seed Orchard in the central North Island of New Zealand. These clones had been Propagated as rooted cuttings and grafts. UMCY was found to be under both environmental and genetic control, with clone accounting for around half of the variation at this site. The broad-sense heritability of UMCY was 59%. Nutrient concentrations in two needle age-classes from the upper and lower crown were measured in four ramets of each of 17 clones selected to cover the range of UMCY severity. There was a negative correlation between UMCY and magnesium (r = -0.60, n = 17, p = 0.01), and a positive correlation with potassium (r = 0.56, n = 17, p = 0.05) and nitrogen (r = +0.75, n = 17, p = 0.01) in upper crown foliage, with the correlations based on clone means. UMCY was absent in clones where foliar magnesium concentrations in 1-year-old needles from the upper crown exceeded 0.10%, but increased with decreasing foliar magnesium, particularly in clones with high foliar potassium or nitrogen. Unknown clonal factors were also involved in UMCY. Broad-sense heritabilities of foliar nutrients were high for potassium, magnesium and calcium (particularly in the lower crown position of trees grown from cuttings), and moderate for other nutrients. Clone means of foliar nutrients differed by more than a factor of two for potassium, magnesium, calcium, boron, and manganese. Marked differences were found between upper and lower crown positions for most nutrients. The scion played a major role in determining foliar magnesium, potassium, manganese, and copper concentrations, while the root stock/graft union played a major role for calcium, zinc, and to a lesser extent nitrogen and phosphorus. Needle retention was also highly clonal, with a broad-sense heritability of 68%. Clones with low needle retention had higher potassium concentrations, both in upper and lower crown foliage, and significantly more UMCY than healthy clones. Part of the clonal variation in diameter at breast height (dbh) was related to UMCY, with healthy clones being larger in mean dbh than clones with severe UMCY. Dbh increased with increasing needle retention, while the concentrations of foliar nitrogen, phosphorus, and potassium correspondingly decreased. We conclude that some genotypes of P. radiata are pre-disposed to UMCY at this site, owing to the high K:Mg and N:Mg ratios in upper crown foliage. Large clonal variation in UMCY indicates that considerable opportunity exists for improving tolerance to UMCY through vegetative propagation of tolerant P. radiata genotypes.

Spray adjuvants can be employed in the foliar application of fertiliser to ensure adhesion of aqueous sprays to the waxy surfaces of foliage (wetters), to improve coverage of spray on foliage (spreaders), to minimise weathering of fertiliser deposits on foliage (stickers/extenders), and to increase the uptake of fertiliser into foliage (humectants, pH modifiers, and penetrants). Even with improved formulations using effective adjuvants, foliar fertilisers must be regarded as supplements to overcome deficiencies in micronutrients, and to boost macronutrients at critical physiological stages, rather than as substitutes for soil-applied fertilisers.

Thinning experiments are difficult to analyse thoroughly. Problems arise because different densities are deliberately created at the outset of the trial. Multiple measures, usually unevenly spaced in time, are subsequently obtained from the experiment. Consequently, analyses of variance are essentially irrelevant because of the very nature of the treatments, and co variance is compromised in that post-thinning covariates will be strongly correlated with treatments. Efficient analyses can be obtained, however, by modelling each plot through time by use of sigmoid functions or orthogonal polynomials, then analysing the respective coefficients by ANOVA or discriminant techniques. These latter ideas were applied to a dataset obtained from a Pinus radiata D.Don thinning experiment in the Northland region of New Zealand, where stocking densities of 200, 350, 500, and 1200 stems/ha were established in four randomised blocks. Basal area and mean top-height measures from ages 5 to 11 were summarised by orthogonal coefficients, but only after the raw data were adjusted by covariance, using pre-thinning basal area per hectare as a covariate. A canonical discriminant analysis isolated the 200 stems/ha blocks as having lower growth in both basal area and mean top-height development. From a sample of sectionally measured trees, it was established that the 200 stems/ha blocks also had significantly lower stand form-factors. These results suggest design of thinning experiments could be enhanced by blocking the experimental plots with respect to initial growing stock, prior to any treatment.

An asynchronism is evident in Pinus radiata D. Don between the seasonal discontinuities for height and stem diameter growth respectively. For stem diameter growth, a clear discontinuity which consistently arises in midwinter is visible in the outer boundary of latewood in a growth ring. For height growth, however, the discontinuity is often less clear, but where it is externally visible it typically arises in summer. Where substantial "autumn" height growth occurs, the asynchronism can generate a major discordance between annual growth stages for height and diameter growth; this can cause confusion in stem analysis and potentially biases estimates of stem volume increments. The extent of the discordance can be influenced by moisture regime, soil fertility, temperature, latitude, genotype, ontogenetic stage, shoot vigour, and tree size.

This work was carried out to examine the hypothesis that differences in Agrobacterium tumefaciens susceptibility observed among Pinus radiata D.Don clones and families after stem inoculation in vitro can be attributed to differences in growth rate at the time of inoculation. Agrobacterium tumefaciens strain 542 was used to inoculate in vitro shoots of 90 clones divided among 14 full-sib P. radiata families. The significant influence of host genotype at the clone and family levels on susceptibility of P. radiata to A. tumefaciens was confirmed, and further evidence was found that growth rate at time of inoculation is important. Significant correlations between growth rate at time of inoculation and gall frequency illustrated the tendency for families (r=0.72, p<0.01) and clones (r=0.58, p=0.01) with rapidly growing shoots to be more susceptible to the bacterium. Analysis of covariance, however, showed that genotype influenced susceptibility over and above its effect on growth rate, pointing to a genotypic component of resistance that is independent of growth rate.