浅谈当前森林覆盖率计算的两个公式

介绍计算森林覆盖率的2个公式,指出应该用(2)式计算森林覆盖率.分析了有林地面积、国家特别规定灌木林地面积、灌木林地面积与森林覆盖率的关系.     

杉木人工林地力维持及更新技术研究

通过对土壤和杉木幼林调查分析结果表明 ,炼山、全垦初期表层土壤水分物理状况得到一定的改善 ,速效性养分大量增加 ;1年后 ,土壤表层水分物理性能变差 ,速效养分流失 ,土壤肥力逐渐下降。不同营林措施组合处理的杉木幼林生长 ,在树高、胸径、单株材积平均生长量上有差异 ,经方差分析 ,胸径、单株材积生长量有显著性差异 ,而树高生长量差异不显著     

提高浑善达克沙地飞播治沙造林成效的初步研究

京津风沙源治理工程启动实施以来,飞播治沙造林种草作为治理浑善达克沙地的一项主要技术得到了大面积的推广应用,并已取得了明显成效。本文根据近年来浑善达克沙地飞播治沙造林情况,就飞播治沙造林中几个关键技术进行了初步研究,对提高浑善达克沙地的飞播成效、加快该地区沙地治理速度具有一定的意义。     

小陇山林区主要林分对降水的再分配

选择锐齿栎、油松、华山松和落叶松林分为对象，系统同步观测了大气一次性降水过程中，不同郁闭度梯度林分群体的林冠透过降水、树干流量、林冠层截留量与大气降水历时、降水强度变化的基本数据。用数量级化理论(I)和线性方程，动态地描绘出各分量随大气降水变化而变化的趋势。揭示出林分对降水的再分配以及求算1年内不同时段林地补给水量的可靠方程。     

阻燃剂浸渍处理木材方法研究

本研究以ZR-M-301型木材阻燃剂为浸渍药液,樟子松和水曲柳为木材试样,选择常压浸渍、压力浸渍、微波处理后常压浸渍、超声波加压浸渍和微波处理后超声波加压浸渍五种木材阻燃处理方法,经过试验,探索在生产阻燃木材的浸渍方法中引入微波和超声波技术的可行性,找到效果好的木材阻燃处理方法.本研究的创新点是将微波处理与超声波辐射技术应用于木材阻燃处理中,利用微波加热处理改善木材构造的渗透性能,利用超声波的空化作用强化阻燃剂浸入性能,并提出了新的技术路线.     

河南桧柏嫩枝“全光雾”扦插育苗试验初报

河南桧柏采用嫩枝“全光雾”扦插育苗，试验表明：对难生根珍贵树种用此法育苗可大大缩短育苗周期，提高苗木产量和质量，应大力推广此种育苗方法。     

森林生态效益计量评价的理论方法概述

森林生态效益计量评价是对一定时期森林所提供的生态效益大小的计量。文章论述了森林生态效益计量评价的理论和方法。为了使评价结果更真实客观,从而能为社会承认和接受,提出应从森林生态效益划分标准问题、综合效益定量问题、林龄动态分析等方面进行深入的研究。     

基于互惠式校企合作的技能培训体系架构--以家具制造业为例

基于互惠模式,通过整合校企资源、调整组织形式等措施,对校企合作中的技能培训提出改进思路,探索家具制造业实用人才的培养模式。     

Effects of supplementation with green tea by‐products on growth performance,meat quality,blood metabolites and immune cell proliferation in goats

Forty‐eight castrated male goats were used to determine the effects of feeding green tea by‐products (GTB) on growth performance, meat quality, blood metabolites and immune cell proliferation. Experimental treatments consisted of basal diets supplemented with four levels of GTB (0%, 0.5%, 1.0% or 2.0%). Four replicate pens were assigned to each treatment with three goats per replicate. Increasing dietary GTB tended to linearly increase the overall average weight gain and feed intake (p = 0.09). Water holding capacity, pH and sensory attributes of meat were not affected by GTB supplementation, while cooking loss was reduced both linearly and quadratically (p < 0.01). The redness (linear; p = 0.02, quadratic; p < 0.01) and yellowness (quadratic; p < 0.01) values of goat meat were improved by GTB supplementation. Increasing dietary GTB quadratically increased protein and decreased crude fat (p < 0.05), while linearly decreased cholesterol (p = 0.03) content of goat meat. The proportions of monounsaturated fatty acid, polyunsaturated fatty acid (PUFA) and n‐6 PUFA increased linearly (p < 0.01) and n‐3 PUFA increased quadratically (p < 0.05) as GTB increased in diets. Increasing dietary GTB linearly increased the PUFA/SFA (saturated fatty acid) and tended to linearly and quadratically increase (p ≤ 0.10) the n‐6/n‐3 ratio. The thiobarbituric acid‐reactive substances values of meat were lower in the 2.0% GTB‐supplemented group in all storage periods (p < 0.05). Dietary GTB linearly decreased plasma glucose and cholesterol (p < 0.01) and quadratically decreased urea nitrogen concentrations (p = 0.001). The growth of spleen cells incubated in concanavalin A and lipopolysaccharides medium increased significantly (p < 0.05) in response to GTB supplementation. Our results suggest that GTB may positively affect the growth performance, meat quality, blood metabolites and immune cell proliferation when supplemented as a feed additive in goat diet.     

Effects of pistachio by‐products on digestibility,milk production,milk fatty acid profile and blood metabolites in Saanen dairy goats

The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile.