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.     

Estimating individual tree heights of sugi (Cryptomeria japonica D. Don) plantations in mountainous areas using small-footprint airborne LiDAR

Recently, it was shown that individual tree heights could be accurately estimated using small-footprint airborne light detection and ranging (LiDAR) remote sensing. Because most of the areas studied previously were limited to flat terrain, we investigated the accuracy of LiDAR-derived individual tree height estimates for different types of topographical features in mountainous forests with a steeper and more complex topography. Several middle-aged (40–50 years old) sugi (Cryptomeria japonica D. Don) plantations are found in the mountainous regions in Japan; hence, we chose 48-year-old sugi plantations to investigate the accuracy of these estimates. The surveyed area was divided into three types of topographical features; steep slope (mean slope ± SD; 37.6° ± 5.8°), gentle slope (15.6° ± 3.7°), and gentle yet rough terrain (16.8° ± 7.8°). Before estimating tree heights, the number of detected trees within each topographical feature was researched. In each of these terrains, the percentage of trees detected correctly was 74%, 86%, and 92%; the average error between LiDAR-derived and field-measured tree heights was 0.227m, –0.473m, and –0.183m; and the accuracy of the LiDAR-derived tree height estimates, given as root mean square error (RMSE), was 0.901m, 0.846m, and 0.576m, respectively. Consequently, the procedure presented in this study could detect most canopy trees and estimate individual tree heights with an accuracy better than 1m, even in a forest with a mean slope angle of approximately 38°; thus, indicating that small-footprint airborne LiDAR will be a useful tool for accurately estimating the heights of individual canopy trees in sugi plantations in mountainous areas.     

Experiments in rooting bishop pine (Pinus muricata D. Don) cuttings

Presented here are results of rooting studies using hedges established from juvenile seedlings of blue and green foliaged bishop pine (Pinus muricata D. Don) from Mendocino and Sonoma Counties, California. Rootability, averaged over all clones and all setting dates, was 88%. The average time for 50% of the cuttings to root was 6 months. In general, cuttings began to root rapidly in late winter/early spring. The time of year when cuttings were set determined how soon they began a phase of rapid rooting, with cuttings set in winter and early spring beginning faster than other setting dates. The period of rapid rooting lasted 2–3 months until mid/late summer, beyond which time, rooting was slow. Population and family differences in rooting were not significant; differences in rooting among clones, however, were large and significant. Analyses of clones in two experiments indicated that rooting was heritable.     

Forest characteristics affecting the rate of shoot pruning by the pine shoot beetle (Tomicuspiniperda L.) in Pinus radiata D. Don and P. sylvestris L. plantations

Different variables, such as altitude and presence of defoliators,were studied in Bizkaia (northern Spain) in order to assessthe susceptibility of Pinus radiata (D. Don) and P. sylvestris(L.) stands to Tomicus piniperda (L.) (Coleoptera: Scolytidae).Altitudes higher than 400 m, presence of logs, degree of thinningand incidence of fires, all increased the susceptibility ofP. radiata monocultures to shoot attack by T. piniperda. P.sylvestris plantations were more affected at alti tudes lowerthan 400 m and by poor forest hygiene. The presence of the processionarymoth (Thaumetopoea pityocampa Den and Schiff.) had a significanteffect on the rate of shoot pruning on the trees; vigorous treesand those with bare leader were more affected by the bark beetleattack if T. pityocampa larvae were feeding on their needles,while trees with dominance taken by the side shoots were lessattacked when moth larvae were present.     

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.     

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 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.     

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。     

Lignin distribution across tracheid cell walls of poorly lignified wood from deformed copper deficient Pinus radiata (D. Don)

Summary Lignin topochemistry of tracheid walls from a deformed, copper deficient Pinus radiata (D. Don) tree was examined by linescan and point analyses using a Scanning Electron Microscope and Energy Dispersive Spectrometry. Both opposite and compression wood had abnormal lignin distributions compared to those observed in normal wood from a straight tree. Lignin contents in the compound middle lamella were lower than lignin contents in the secondary wall in both opposite and compression wood tracheids.One of us (G. D.) held a Commonwealth Forestry Postgraduate Research Award during this study. The research was supported in part by a grant from the Reserve Bank of Australia Rural Credits Development Fund, the Pine Fund, and members of the forest industry     

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.     

Root reinforcement in plantations of Cryptomeria japonica D. Don: effect of tree age and stand structure on slope stability

The role of vegetation in preventing shallow soil mass movement is now fairly well understood, particularly at the individual plant level. However, how soil is reinforced on a larger scale and the influence of changes in vegetation over time has rarely been investigated. Therefore we carried out a study on the temporal and spatial changes within stands of Cryptomeria japonica D. Don, growing in the Sichuan province of China, an area where shallow landslides are frequent.     

Use of sewage sludge in silvopastoral systems under Pinus radiata D. Don: soil,tree growth,and pasture production

Agroforestry Systems - Short-term production in silvopastoral systems is often limited due to inappropriate soil-fertility management. Sewage sludge fertilisation could enhance productivity of...     

Predicting individual stem volumes of sugi (Cryptomeria japonica D. Don) plantations in mountainous areas using small-footprint airborne LiDAR

This study investigated which predictor variables with respect to crown properties, derived from small-footprint airborne light detection and ranging (LiDAR) data, together with LiDAR-derived tree height, could be useful in regression models to predict individual stem volumes. Comparisons were also made of the sum of predicted stem volumes for LiDAR-detected trees using the best regression model with field-measured total stem volumes for all trees within stands. The study area was a 48-year-old sugi (Cryptomeria japonica D. Don) plantation in mountainous forest. The topographies of the three stands with different stand characteristics analyzed in this study were steep slope (mean slope ± SD; 37.6° ± 5.8°), gentle slope (15.6° ± 3.7°), and gentle yet rough terrain (16.8° ± 7.8°). In the regression analysis, field-measured stem volumes were regressed against each of the six LiDAR-derived predictor variables with respect to crown properties, such as crown area, volume, and form, together with LiDAR-derived tree height. The model with sunny crown mantle volume (SCV) had the smallest standard error of the estimate obtained from the regression model in each stand. The standard errors (m³) were 0.144, 0.171, and 0.181, corresponding to 23.9%, 21.0%, and 20.6% of the average field-measured stem volume for detected trees in each of these stands, respectively. Furthermore, the sum of the individual stem volumes, predicted by regression models with SCV for the detected trees, occupied 83%–91% of field-measured total stem volumes within each stand, although 69%–86% of the total number of trees were correctly detected by a segmentation procedure using LiDAR data.     

辐射松人工幼林生物量和生产力研究

本文对岷江上游干旱河谷区引种栽培的5 a生辐射松幼林生物量和生产力进行了测定和研究,用"平均标准木法"和"样方收获法"分别调查了乔木层、灌木层、草本层、苔鲜层和凋落物层的生物量.据调查数据,用"相对生长法则"建立了乔木层单株立木及其各器官干重的回归方程,方程的精度均在97%以上.同时还研究了林分平均净生产量和产量结构.结果表明岷江上游干旱河谷区5 a生辐射松人工林分生物量平均为19.507 t/hm2,净生产量为3 902.40kg/(hm2·a).其中,乔木层生物量为8.510 t/hm2,占林分总量的43.62%;净生产量1.702 t/(hm2·a),占林分净生产量的43.63%.灌木的生物量和净生产量分别为2.171 t/hm2、434.20 kg/(hm2·a);草本的生物量和净生产量分别为8.091 t/hm2、1 618.20 kg/(hm2·a);苔鲜层的生物量和净生产量分别为0.464 t/hm2、92.80kg/(hm2·a);凋落物的生物量和净生产量分别为0.271 t/hm2、54.20 kg/(hm2·a).辐射松人工林与同区域同龄油松和岷江柏相比,其生物量和生产力都远高于它们.     

Wood quality assessment of Pinus radiata (radiata pine) saplings by dynamic mechanical analysis

Wood Science and Technology - The use of dynamic mechanical analysis was explored as a possible method of screening for wood quality in breeding programmes. Viscoelastic properties along the grain...     

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.     

A model of the juvenile growth and survival of Pinus radiata D. Don; Adding the effects of initial seedling diameter and plant handling

New Forests - Initial ground line diameter (GLD) of Pinus radiata D.Don and the care of treesduring transport to the field growing siteaffect subsequent tree growth and survival. Anexisting model...