A review of measurement options for multipurpose trees

There is an urgent need to standardize the methods used to assess the growth of multipurpose trees. Most of the standard methods so far described have been developed specifically for use in multilocational trial networks. This paper was prepared for the F/FRED/ICRAF Workshop on MPTS Assessment Methods, held in Thailand in May 1991 to develop internationally-recognised standards for assessment methodology. It critically reviews the methods prescribed by different networks for height and diameter measurement, and for biomass estimation, giving researchers a range of methodological options to consider and re-emphasizing the need, all too often neglected, to define assessment methods clearly and unambiguously.     

明溪县杉木马尾松商品材立木材积表编制的研究

应用树干分段的二元形数函数的削度方程、商品材材积方程和树干总材积方程的一致性方程系统编制明溪县杉木、马尾松的商品材立木材积表。既能充分利用公开发表的有效的测树信息和数表 ,又能结合区域的资源调查信息估测一致性系统中的参数 ,且编表的误差分布均匀 ,绝对误差和相对误差小     

Foliar and shoot allometry of pollarded black locust, Robinia pseudoacacia L.

Browse of multipurpose tree species such as black locust could be used to broaden grazing options, but the temporal distribution of foliage has not been adequately studied. Our objective was to determine effects of harvest date, P fertilization (0 and 600 kg ha⁻¹ yr⁻¹), and pollard height (shoots clipped at 5-, 50-, and 100-cm above ground) on foliar and shoot allometry of black locust. The experiment was conducted on a naturally regenerated 2-yr-old black locust stand (15,000 trees ha⁻¹). Basal shoot diameter and foliar mass were measured monthly in June to October 2002 and 2003. Foliar and shoot dry mass (Y) was estimated from basal shoot diameter (D) by the function Y = aD ^b , with regression explaining ≥95% of variance. Allometry of foliar mass was affected by harvest date, increasing at a greater rate with D in September than in June or July, but not by P fertilization or pollard height. Foliar mass was predicted best by month-specific equations for the June to October growth interval. Allometry of shoot dry mass was unaffected by harvest date, P fertilization, or pollard height. These equations could be used as a first approximation of foliar and shoot mass for pollarded black locust.     

Ⅰ-72杨人工林的投入产出及经济成熟龄

本文讨论了山东省沂南县沂河林场不同密度Ⅰ-72杨人工林的投入产出及经济成熟龄。投入分为一次性投入和每年投入。一次性的总投入量为2 33 1.00元/ha,其中整地占84％;平均年投入为253.21元/ha·a,其中追肥占74％。文中还计算了长期占用资金的复利。对各密度的年投入量、年生长量、年产值、年均净产值及其年动态进行了研究,同时做了林木的年均生长量和年均净产值数学模拟。杨树人工林在造林后第三年才能获得利润。数量成熟龄为6～10年,年均最高生长量可达25.252 1 m~3/ha·a。经济成熟龄为6～7年,年均最高净产值可达6 110.52元/ha·a。杨树人工林的数量成熟龄与经济成熟龄主要受密度及投入成本的影响。     

Potential long-term growth gains from early clump thinning of coppice-regenerated oak stands

A study was established in the Missouri Ozarks to evaluate coppice regeneration of oak. Five years after a 32-year-old stand was clearcut and regenerated naturally through stump sprouts, the dominant sprout on each stump was identified based upon height. Treated plots were thinned to the single dominant sprout on each stump whereas control plots were not thinned. Twenty-five years later the largest 247, 371, 494, and 618 stems per ha were examined and height of the dominant sprout at age 5 was found to be strongly related to dbh at age 30 in both thinned and unthinned plots. However, in the thinned plots, the largest 494 stems per ha were on average 11%, 28%, and 58% greater, respectively, in height, dbh, and volume compared to similar dominant sprouts in unthinned plots. Logistic regression analysis was used to develop curves for the evaluation of potential gains from clump thinning. In this analysis, the average height of a stand at age 5 was used to estimate thinning gains at age 30.     

Height–diameter equations for boreal tree species in Ontario using a mixed-effects modeling approach

Height–diameter relationships based on stand characteristics (trees/ha, basal area, and dominant stand height) were investigated for balsam fir, balsam poplar, black spruce, jack pine, red pine, trembling aspen, white birch, and white spruce using data from permanent growth study plots in northern Ontario, Canada. Approximately half the data were used to estimate model parameters with the rest used for model evaluation. Multiple Chapman–Richards functions with parameters expressed in terms of various stand characteristics were fit to determine the best models for predicting height.     

Application of the pipe model theory to non-destructive estimation of leaf biomass and leaf area of pruned agroforestry trees

The relationship of branch cross sectional area (CS) to leaf biomass (LM) and leaf area (LA) was studied in three agroforestry tree species,Calliandra calothyrsus Maissn.,Erythrina berteroana Urban andErythrina poeppigiana (Walpers) O.F. Cook, to develop a non-destructive method for the estimation of LM and LA for trees managed with periodic pruning. Variation in these relationships was observed according to the bifurcation level and, in theErythrina spp., by clone. All the relationships were linear except the CS-LM relation in small branches ofE. poeppigiana, where it was initially exponential. At main branch level the relationship of CS to LM and LA was linear in all cases but the regression parameter values varied between species and clones, with determination coefficient (R²) 0.88–0.99. It was concluded that the ratio of main branch CS to LM and LA can be used for non-destructive estimation of the latter variables. The method has the additional benefit that the regression parameter value reflects the allocation of dry matter within a tree and, consequently, may give indications about its possible uses in different agroforestry systems.Work carried out at the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Turrialba, Costa Rica.     

天然林直径分布的线性表达及其应用

利用非线性函数的线性化方法,使传统的天然林直径分布的反"J"型曲线转化为直线形式,并探讨了直线参数变化的直观表现。通过对长白山天然林123个固定试验地林分直径分布的线性拟合,平均相关系数为0.98,表明天然林的直径分布线性化表达是可行的。可利用参数设计择伐株数和预估采伐前后的直径分布。参数在天然林择伐作业设计中可操作性强,研究结果可以为天然林经营,特别是为择伐作业提供依据。     

阔叶树小径材热压干燥工艺的研究

通过对荷木和米槠两种华南地区常用阔叶树小径材薄板材热压干燥工艺的研究，探讨热压干燥工艺参数对小径材板材干燥质量（包括密度，厚度压缩率，尺寸稳定性及部分力学性能）的影响，试验结果表明，热压干燥工艺可以大大改善小径材的物理力学性能。     

菌根剂对桃、李、柰果实重量及病虫抗性的影响

为探索果树采用何种施肥方法 ,具较好经济效益 ,在桃、李、柰等果树上 ,选择Pt菌根剂、超大生物菌肥、肥力高和常规施用复合肥进行比较实验 ,发现Pt菌根剂具有较好经济效益。