A growth model for Pinus radiata D. Don stands in north-western Spain

A dynamic whole-stand growth model for radiata pine (Pinus radiata D. Don) stands in north-western Spain is presented. In this model, the initial stand conditions at any point in time are defined by three state variables (number of trees per hectare, stand basal area and dominant height), and are used to estimate total or merchantable stand volume for a given projection age. The model uses three transition functions derived with the generalized algebraic difference approach (GADA) to project the corresponding stand state variables at any particular time. These equations were fitted using the base-age-invariant dummy variables method. In addition, the model incorporates a function for predicting initial stand basal area, which can be used to establish the starting point for the simulation. Once the state variables are known for a specific moment, a distribution function is used to estimate the number of trees in each diameter class by recovering the parameters of the Weibull function, using the moments of first and second order of the distribution. By using a generalized height-diameter function to estimate the height of the average tree in each diameter class, combined with a taper function that uses the above predicted diameter and height, it is then possible to estimate total or merchantable stand volume.     

Using density management diagrams to assess crown fire potential in Pinus pinaster Ait. stands

Context

Density management diagrams (DMDs) are useful for designing, displaying and evaluating alternative density management regimes for a given stand-level management objective. The inclusion of variables related to crown fire potential within DMDs has not previously been considered.

Aims

The aim of this study was to include isolines of variables related to crown fire initiation and spread in DMDs to enable identification of stand structures associated with different types of wildfire.

Methods

Biometric and fuel data from maritime pine (Pinus pinaster Ait.) stands in NW Spain were used to construct DMDs. Different surface and crown fire behaviour models were used together to estimate crown fire potential.

Results

The crown fire potential varied greatly throughout development of the maritime pine stands. Low stands were more prone to crowning. The type of crown fire was mainly determined by stand density.

Conclusion

The DMDs developed can be used to identify relationships between stand structure and crown fire potential, thus enabling the design of thinning schedules aimed at reducing the likelihood of crowning.     

Growth response of Pinus pinaster Ait. to climatic variables in central Spanish forests

? The effect of climatic variables (temperature and precipitation) on radial growth of the Mediterranean Maritime pine (Pinus pinaster Ait.) was studied using dendrochronological techniques in the Iberian Peninsula.

? Ten tree-ring width chronologies, along the central distribution area of the species, were built. Chronology variability was analysed using Principal Component Analysis (PCA) for the period 1952–2005.

? The first principal component (PC1) explained 56% of tree-growth variability. Tree-growth association with climate was analysed at regional and local scales using correlation coefficient and bootstrapped response functions.

? Radial growth at both scales was positively correlated with rainfall during and prior to the growing season at all sites, and with summer rainfall before the growing season at five sites. Mean temperature effect changed according to the sampling site, from non-significant at the highest sites to significant (positive relationship in winter) at the lowest sites. Growth season temperature also had a negative effect.

? The Kalman filter was applied to estimate changing association between growth and climate over-time. Results suggested a change in association, initiated in the 80s, from non-significant to significant (*p < 0.05) at six of the sampling sites.

? Pinus pinaster is an accurate species for analysing tree-growth association with climate and for studying plant behaviour under global change conditions.

     

新西兰辐射松的无性繁殖

新西兰的辐射松人工林举世闻名。辐射松的遗传改良和无性繁殖研究为发展辐射松起了巨大作用。本文扼要介绍了新西兰辐射松无性繁殖的研究历史、大规模应用的原困以及主要技术方法。     

Effects of Eucalyptus obliqua (L'Herit) density on young stands of even-aged Pinus radiata (D. Don)

In a 10-year-old Pinus radiata plantation, increasing densities of Eucalyptus obliqua, a woody weed species, caused reductions in the canopy leaf area and total stem volume of P. radiata. As the density of E. obliqua increased stand volume (the sum of stem volumes of the two species) was constant, but the sum of projected leaf area of the two species decreased. Higher E. obliqua density also resulted in higher mean height to diameter ratio of P. radiata. With increasing E. obliqua density the size distribution of P. radiata became more positively skewed and the size hierarchy of P. radiata increased. The effects of E. obliqua density on P. radiata are more likely due to below-ground competition than competition for light above-ground. Understanding the effects of E. obliqua density on the characteristics of P. radiata can benefit weed control programs and subsequent management of plantations with naturally regenerated E. obliqua.     

Improving harvester estimates of bark thickness for radiata pine (Pinus radiata D.Don)

Harvesters estimate bark thickness primarily from diameter over bark (DOB) and use it to estimate log volume and value. Harvester bark thickness estimation errors can reduce returns through poor bucking optimisation and out-of-specification logs. Radiata pine bark thickness data from harvested logs and permanent sample plots (PSP) were analysed to determine best-fit coefficients for current and potential future harvester bark thickness models. The most suitable current harvester bark thickness model for radiata pine is: double bark thickness = b ₀ + b ₁*DOB (the ‘DOB model’). This describes a straight line, whereas radiata pine bark relative to DOB is thicker near the stem base and consistent over the remainder. PSP data set coefficients for this model overestimated upper stem bark thickness and underestimated lower stem values. The harvester model for Scots pine bark fitted better than the DOB model for diameters <400 mm but performed poorly for larger logs, as it is restricted to trees with a diameter at breast height <590 mm. Two better models were identified: (1) a model using relative height to account for bark thickness changes with height, and (2) implementing separate DOB models for the bottom 10% and top 90% of the stem split by relative height. These approaches require approval by the StanForD committee to be implemented. Prior to approval, the upper 90% model coefficients could be applied to the entire stem to improve upper 90% stem volume and value predictions at the expense of the lower 10%. Further research will determine if this approach produces acceptable results when optimising bucking. Increasing variability of bark thickness estimates with increasing DOB in the PSP data set may reflect manual measurement errors with thicker bark or may show that additional explanatory variables are needed. Efforts to identify new variables would need to be weighed against additional returns and probable reductions in numbers of larger trees by as the clearfell age is reduced.     

Modelling the site index of Pinus pinaster plantations in Turkey using ecological variables

The determination of site productivity in forest ecosystems plays a crucial role in resource management.This study was carried out to identify relationships between site characteristics and height growth of Corsican maritime pine(Pinus pinaster Ait.) plantations in Turkey.Sixty-nine sample plots 20 years of age were selected from locations with different inclinations,aspects,elevations,slope positions and site class.Soil samples were taken at various depths.Height and age were measured on a dominant tree after felling in each plot.Physical and chemical properties of the soil were determined.Relationships between site index(SI_(25)) and physiographic factors,climatic attributes as well as soil properties were evaluated using correlation analysis and multiple regression analysis.Site index was significantly related with annual precipitation,mean spring rainfall,rainfall June to September,rainfall of the driest month,length of the dry period,mean maximum temperature,mean temperature of the warmest month,stoniness of the soil,sand,silt,clay,pH,electrical conductivity,and available water capacity.Multiple regression accounted for 57.9% of variations in height growth.The models obtained can be used to determine the site index of potential areas in Turkey for maritime pine.It can be said that the productivity of maritime pine may decline in the future due to global climate change.     

Seasonal changes in lignin distribution during tracheid development in Pinus radiata D. Don

Summary Lignin distribution in developing tracheids of Pinus radiata was studied throughout the growth' season using quantitative interference microscopy. The pattern of lignification remained constant although the number of lignifying cells varied reaching a maximum in summer. Lignification of the secondary wall of latewood tracheids was incomplete at the onset of winter. Each stage of lignification was preceded by deposition of carbohydrates with lignification of the middle lamella starting after S1 formation and lignification of the secondary wall starting after S3 formation. Lignification of the middle lamella was completed before the start of lignin deposition in the secondary wall. In one of the trees examined, the secondary wall lignified concurrently with the middle lamella and this was associated with a low lignin concentration in the middle lamella of mature cells. The secondary wall reached a mature lignin concentration of 21–22% v/v except in one specimen containing severe compression wood which reached 28% v/v. The cell corner middle lamella reached a mature lignin concentration of 74–87% v/v.     

干旱地带辐射松整地造林研究

经过连续3年采用不同的整地方式对辐射松(Pinus radiataD.Don)造林及幼林生长的试验研究,结果表明:(1)干旱地带采用水平沟、短册状整地比穴状整地造林成活率提高2.4~7.8个百分点,保存率提高1.0~7.6个百分点,高生长量提高7.8 cm~28.4 cm,地径生长量提高0.28 cm~0.84 cm。(2)水平沟整地比短册状、穴状整地0~100 cm土壤含水量全年分别提高1.29个百分点和2.08个百分点,旱季分别提高1.36个百分点和1.37个百分点,雨季分别提高1.16个百分点和2.87个百分点;短册状整地比穴状整地0~100 cm土壤含水量全年提高0.80个百分点,旱季提高0.01个百分点,雨季提高1.72个百分点。     

Pine needle consumption and bark stripping by sheep grazing annual pastures in young stands of widely spaced Pinus radiata and P. pinaster

The consumption of the pine needles and the stripping of bark by sheep grazing annual pastures in three open stands of P. radiata and one of P. pinaster were measured. The P. radiata were four years old and the densities were 250, 500 and 750 trees ha^-1. The P. pinaster included two, three and four year-old trees and the density was 440 trees ha^–1.Needles were eaten immediately after the sheep were admitted and this continued throughout the year. Within ten weeks of the start of winter grazing, sheep stocked at 7–10 ha^–1 had eaten about half of the accessible needles on both species where densities were less than500 trees ha^–1. The estimated consumption was about 260 g sheep^–1 day^–1 for the P. radiata. Bark stripping then commenced and continued throughout spring and summer on most plots. In some plots at low tree density, bark was stripped from more than 35% of the trees. In denser stands, needle consumption per tree was less and bark was stripped from less than 5% of the trees.Bark damage was most common on the smaller trees, and severity of stripping was negatively correlated with tree size. Of all the trees with bark damage, 22% of the P. pinaster and 14% of the P. radiata had more than half of the stem circumference stripped. A number of these will probably suffer both stem distortion and growth retardation, and some may die.Methods of reducing the incidence of bark damage are discussed.     

Field Performance of Pinus radiata D. Don Produced in Nursery with Different Types of Containers

We have studied the development in nurseries of containerized Pinus radiata produced with different container systems in order to choose the most suitable system for producing well-balanced plants with an optimal root system. At the end of the production period, significant differences were found in morphological responses among the seedlings to the various container characteristics. Seedlings grown in containers that permitted lateral air puning presented less growth and lower biomass production. However, root deformations were more frequent and severe in plants produced in closed-wall containers. Field performance was likewise mainly affected by container type and plant growth rate, as faster grown plants showed more problems of stability than plants with a balanced root and stem development.     

Lignin distribution in wood from a progeny trial of genetically selected Pinus radiata D. Don

Summary Cell wall lignin distribution was assessed in Pinus radiata wood using quantitative interference microscopy. Three groups of trees were examined. Five trees, offspring of NZ clone 850-55, and five trees of NZ 850-55 crossed with several parents of the Guadelupe provenance, were compared with five trees of unselected P. radiata. Lignin concentration in the cell corner middle lamella region was significantly lower in both offspring groups of NZ 850-55 when compared with the unselected control trees. No difference in S2 lignin concentration was observed among the three groups. This result represents the first indication that variations in lignin distribution are genetically controlled in pines.The author gratefully acknowledges the assistance of Dr. C. J. A. Shelbourne, Mr. G. D. Young, FRI, and Mr. R. S. Foster, Papro (NZ), during the course of this work     

A crown profile model for Pinus radiata D. Don in northwestern Spain

A crown profile model was developed for radiata pine (Pinus radiata D. Don) in Galicia (northwestern Spain). Data from 443 trees located in 56 permanent plots, established by the Unidade de Xestión Forestal Sostible (UXFS) of the University of Santiago de Compostela in plantations of this species in the region, were used. The crowns of the trees were measured by a visual method based on similar triangles. Both simple geometric shapes and mathematical equations were used to describe the crown profiles. As crown profile models usually require variables that are expensive to measure, equations to estimate the maximum crown radius and the height to the maximum crown radius were also developed, using other easily measured tree and stand variables. Several models were fitted using a system of equations approach and accounting for an autocorrelated, heteroscedastic error structure. The selected crown profile model consists of a system of two allometric equations for the crown below (primarily shade needles) and above (primarily sun needles) maximum crown radius. The model explained 88% of the variability in crown radius with a mean error of 0.24 m.     

Influence of copper on root growth and morphology of Pinus pinea L. and Pinus pinaster Ait. seedlings

We assessed the effects of Cu on root growth and morphology of stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Ait.) seedlings grown in culture solutions supplied with 0.012 (control), 0.1, 1 or 5 micro M CuSO(4). The presence of 5 micro M Cu in the nutrient solution completely inhibited root growth of both species within 3 days. In both species, taproot elongation was reduced in the presence of 1 micro M Cu, although partial growth recovery occurred after 7 days of treatment. The presence of 0.1 micro M Cu in the culture solution slightly enhanced root elongation in P. pinaster, but did not significantly influence root elongation in P. pinea. In both species, root weight per unit length increased in response to Cu exposure, and in P. pinaster, root diameter was significantly increased. The Cu treatments also affected lateral root number and length. In the presence of 1 micro M Cu, both species formed only short lateral primordia. The 1 micro M Cu treatment increased the lateral root index (number of roots per cm of root length) of P. pinaster, but decreased that of P. pinea, compared with control values. Neither the 0.1 nor 1 micro M Cu treatment had a significant effect on the mitotic index of either species. We conclude that cell elongation is more sensitive to Cu than cell division. Cell membrane damage, as indicated by Trypan blue staining, occurred after 10 days of exposure to 1 micro M Cu.     

沙地海岸松在山东和浙江引种试验研究

通过对引种沙地海岸松的育苗和造林试验研究,结果表明:在沙地海岸松第一年幼苗期生长中,播种密度对其影响不大,而适度遮荫(80%透光率)有利于海岸松幼苗的生长。沙地海岸松在养分含量高、偏酸性土壤中生长占优势,且在温州地区育苗及造林后的高与地径生长均显著高于蓬莱地区。海岸松容器苗的造林成活率显著高于裸根苗;不同海岸带造林后,其生长速度在海阳市最快,其次是莱州市和烟台市。     

Methods for the very early selection of Pinus radiata D. Don. for solid wood products

? Introduction

There has been an increasing interest in very early selection of radiata pine to reduce the breeding cycle for solid wood products. For such selection, new approaches are required to assess wood quality in wood from very young stems.

? Methods

Nursery seedlings of clones of radiata pine were grown in leant condition using two leaning strategies for 18–20 months. Opposite wood and compression wood were isolated from the leaning stems and tested for dynamic modulus of elasticity, density, longitudinal shrinkage, volumetric shrinkage and compression wood area using new methods evolved for testing small size samples quickly and reliably. The methods were tested for their efficiency in differentiating clones by their wood properties.

? Results

Leaning of stems provided distinct opposite and compression wood for testing. Automated image analysis method used for compression wood area assessment was found to be a quick and effective method for processing large number of samples from young stems. Compression wood was characterised by high basic density, high longitudinal shrinkage and low volumetric shrinkage than that of opposite wood. Acoustic velocity in opposite wood had a strong negative association with longitudinal shrinkage. The study signifies the importance of preventing mixing of opposite wood with compression wood while assessing wood quality in young stems thus making leaning a critical strategy. The comparison of wood properties of opposite wood revealed significant differences between clones. Opposite wood of the clone with the lowest dynamic modulus of elasticity exhibited the highest longitudinal shrinkage.

? Conclusion

Significant differences in measurable wood properties between clones suggest the prospects of early selection for solid wood products.     

Impact of local slope and aspect assessed from LiDAR records on tree diameter in radiata pine (Pinus radiata D. Don) plantations

Context

Reliable information on tree stem diameter variation at local spatial scales and on the factors controlling it could potentially lead to improved biomass estimation over pine plantations.

Aims

This study addressed the relationship between local topography and tree diameter at breast height (DBH) within two even-aged radiata pine plantation sites in New South Wales, Australia.

Methods

A total of 85 plots were established, and 1,302 trees were sampled from the two sites. Airborne light detection and ranging (LiDAR) was used to derive slope and aspect and to link them to each individual tree.

Results

The results showed a significant relationship between DBH and local topography factors. At both sites, trees on slopes below 20° and on southerly aspects displayed significantly larger DBHs than trees on steeper slopes and northerly aspects. Older trees with similar heights also exhibited a significant relationship between DBH and aspect factor, where greater DBHs were found on southerly aspects.

Conclusions

The observed correlation between tree DBH and LiDAR-derived slope and aspect could contribute to the development of improved biomass estimation approaches in pine plantations. These topographical variables are easily attained with airborne LiDAR, and they could potentially improve DBH predictions in resource inventories (e.g. stand volume or biomass) and support field sampling design.     

Genetic correlations among juvenile wood quality and growth traits and implications for selection strategy in Pinus radiata D. Don

? Juvenile wood quality in Pinus radiata is affected by factors such as low density, stiffness, and high microfibril angle, spiral grain, and shrinkage. Adverse genetic correlations between growth and wood quality traits remain as one of the main constraints in radiata pine advanced generation selection breeding program.

? Juvenile wood property data for this study were available from two progeny tests aged 7 and 6 y. We estimated the genetic correlations between stiffness, density, microfibril angle, spiral grain, shrinkage in the juvenile core and DBH growth in radiata pine, and) to evaluated various selection scenarios to deal with multiple objective traits.

? Negative genetic correlations were found for modulus of elasticity (MoE) and density with microfibril angle, spiral grain, shrinkage, and DBH. We observed low to moderate unfavourable genetic correlations between all wood quality traits and DBH growth.

? These low to moderate genetic correlations suggest that there may be some genotypes which have high DBH growth performance while also having high wood stiffness and density, and that the adverse correlation between DBH and MoE may not entirely prohibit the improvement of both traits. Results indicate that, in the short term, the optimal strategy is index selection using economic weights for breeding objective traits (MAI and stiffness) in radiata pine.

? In the long-term, simultaneously purging of the adverse genetic correlation and optimizing index selection may be the best selection strategy in multiple-trait selection breeding programs with adverse genetic correlations.

     

Modelling the edge effect in even-aged Monterey pine (Pinus radiata D. Don) stands

Six edge effect models are presented. Modelling results for the edge effect on the DBH, total height, crown height, and basal area in even-aged stands of Monterey pine (Pinus radiata D. Don) are provided. Free edges and edges under external competition pressure were analysed. Model fitting was carried out in two phases. In the first phase, independent fittings for each border type by sampled cardinal point in each stand were carried out to detect differences in edge effect intensity and depth according to edge aspect. In the second fitting phase, the best models selected by edge aspect in the first phase were restricted to estimate the same value for each variable in the stand interior, independently of the border where it was analysed.

The edge effect intensity and depth varied depending on the analysed variable and edge type. Modelling of the edge effect on DBH and total height on free edges of old stands requires a model with independent parameters for each border aspect; the models can be restricted to estimate the average value of each variable in stand interior. A model with independent parameters for each border aspect should be also used for modelling the effect on total height, crown height and basal area for the edges of young stands under external competition pressure. The modelling of basal area and crown height on free edges of old stands, DBH on edges of young stands under external competition pressure, and all variables mentioned on free edges of young stands can be carried out through an average fitting. DBH and basal area are directly affected by stand density; thus, modelling of edge effect on these and others variables which are affected by stand density can improve with the inclusion of a competition index or a point density index.