基于回归与随机模拟的区域森林碳分布估计方法比较

以临安市为例,利用2004年森林资源清查样地数据和同年度Landsat TM影像数据,采用一元二次非线性回归和序列高斯协同模拟方法分别模拟森林地上部分碳密度及其分布,并对模拟结果进行比较分析。结果表明:一元二次非线性回归估计得研究区森林碳储量为2365404.37t,碳密度平均值为9.0000t·hm-2,最大值为73.7144t·hm-2,最小值为0.7156t·hm-2;序列高斯协同模拟得研究区森林碳储量为3291659.83t,碳密度平均值为12.5233t·hm-2,最大值为78.9133t·hm-2,最小值为0.0833t·hm-2;根据2004年森林资源清查样地数据,按随机抽样方法估计研究区森林碳储量为2708897.90t,样地碳密度平均值为10.3065t·hm-2,其最大值为96.9625t·hm-2,最小值为0;序列高斯协同模拟结果更接近地面样地估计结果,而且碳密度分布范围更合理;一元二次非线性回归估计结果与地面样地估计结果之差的累积平方和为9857.4619,而序列高斯协同模拟结果与实测结果之差的累积平方和为8018.4625;序列高斯协同模拟较一元二次非线性回归在估计区域森林碳空间分布...     

浦北县森林植被乔木层碳储量与碳密度研究

通过选设代表性标准地,运用样地调查法对广西钦州浦北县的森林植被乔木层的碳储量和碳密度进行了研究。结果表明:浦北县森林植被乔木层碳密度的特征为阔叶林针叶林小乔木林(油茶林);从森林类型分布来看,天然林的比例大于人工林;浦北县乔木层的总碳储量为3.221×10~7t。     

基于遥感地学模型的辽宁省森林生物量和碳储量估测

通过对森林植被生物量估测遥感模型机理的综合分析,采用2005年辽宁省森林资源连续清查部分样地数据,基于遥感及其派生信息、气象信息、地学信息、林分信息建立了估测森林植被生物量的多元回归模型。得出如下结论:1)根据与样地生物量相关性的高低对MODIS数据植被指数(NVDI)的排序为植被指数的年平均值(NVDI_AVER)、植被生长季节的植被指数的平均值(NVDI_AMD)、植被指数的年内最大值(NVDI_MAX)、植被指数的年内最小值(NVDI_MIN)、植被指数的年内最大值与最小值之间的差值(NVDI_CHA);与生物量相关的气象因子分别为相对蒸散、平均气温和>10℃的积温,其相关系数分别为0.422,0.399和0.394;生物量与坡向、纬度相关性不显著。2)辽宁省森林总生物量为255.774×106t,森林碳储量为127.887×106t。3)从辽宁省森林碳密度空间分布来看,辽宁省森林碳密度呈现出东高西低的趋势,并且碳密度总体上不高,为50 t/hm2以下。     

山西省森林植被碳储量及其动态变化研究

以山西省1995年、2000年和2005年的3期森林资源清查数据为基础,采用生物量换算因子法,研究了山西省森林植被碳储量及其动态变化。结果表明:10年间山西森林的碳储量总体呈上升的趋势。全省森林的总碳储量由1995年的3514.22万Mg增加到2005年的4505.61万Mg。在14个(类)森林优势树种中,栎类、油松和杨树这三者的碳储量占主导地位,合计占山西省森林总碳储量的60%以上。在全部森林中,幼、中龄林及近熟林的碳储量合计约占总量的90%。2005年,人工林碳储量占森林总碳储量的百分比提高了5.28%,全省森林平均碳密度为23.8933~26.3717Mg/hm2。     

基于地统计学和多源遥感数据的森林碳密度估算

【目的】基于遥感影像空间分辨率和地面样地大小不一致的现象,采用地统计学和多源遥感数据进行森林碳密度估算,为MODIS数据在区域森林碳密度估算领域的应用提供参考。【方法】以湖南省攸县为试验区,首先利用基于块的序列高斯协同模拟算法,将25.8 m×25.8 m的样地数据分别上推到250 m×250 m、500 m×500 m和1 000 m×1 000 m;然后将上推后的样地数据分别与MOD13Q1、MOD09A1、MOD15A2数据结合,利用序列高斯协同模拟算法开展区域森林碳密度估算研究;最后将最优结果用于湖南省森林碳密度估算。【结果】Landsat5和MODIS数据与森林碳密度的敏感因子具有高度相似性,排在前3位的分别为1/TM3、1/TM2、1/TM1和1/Band1、1/Band4、1/Band3;与植被指数产品MOD13Q1和MOD15A2相比,多光谱数据Landsat5和MOD09A1在攸县森林碳密度估算方面显示出巨大潜力,估算精度分别为82.02%和75.64%;基于MOD09A1的序列高斯协同模拟算法具有很好的适用性,可用于湖南省森林碳密度的空间模拟,估算精度为74.07%。【结论】采用基于块的序列高斯协同模拟算法,可以实现由地面样地到不同空间分辨率MODIS像元之间的转换;由于空间分辨率的限制,MOD09A1数据在刻画空间细节方面不如Landsat5精细。该研究方法适用于地面调查样地大小和遥感影像空间分辨率不一致的区域森林碳密度估算。     

基于森林资源二类调查的青海乔木林碳储量分析

以青海省森林资源二类调查为基础,结合样地调查资料、解析木资料等,综合应用模型模拟、尺度扩展和GIS等方法,分析青海省乔木林碳储量现状。结果表明,(1)2009年青海省乔木林植被碳储量约为28.55×10~6Mg,平均碳密度约为44.24Mg/hm~2;(2)青海省乔木林碳主要分布在天然林中,占青海乔木林碳库总量的89.83%,碳密度同样以天然林为高(46.19Mg/hm~2);(3)有林地中纯林碳储量最高,占乔木林碳库总量的84.28%;碳密度则以混交林为最高,达60.20Mg/hm~2;(4)青海省四大乔木树种(组)(云杉、圆柏、桦木和杨树)的碳储量占全省乔木林植被碳储量的98.07%,碳密度方面居前5的树种(组)为云杉(74.03Mg/hm~2)、桦木(55.76Mg/hm~2)、油松39.24(Mg/hm~2)、栎类(37.49Mg/hm~2)、圆柏(29.61Mg/hm~2);(5)青海省乔木林主要以中幼林为主,占总面积的63.19%,正处于快速生长阶段。     

贵州华山松林分结构与碳储量动态

以"森林资源连续清查样地数据库(2000—2010)"和"森林资源二类调查数据库(1976—2006)"为基础,研究了贵州省华山松林分结构与碳储量及动态变化。连续清查样地数据分析表明华山松林构件生物量排序为树干>树枝>树根>树叶,华山松林生物量由2000年的0.958×106t增至2010年的2.166×106t,碳储量由2000年的0.518×106t增至2010年的1.165×106t。二类资源调查数据分析表明1976—2006年华山松林生物量从0.297×106t增至3.244×106t,碳储量从0.160×106t增至1.75×106t,不同龄组华山松林生物量和碳密度分布趋势为近熟龄组>中龄组>成熟龄组>幼龄组,华山松纯林生物量和碳密度高于混交林。全省华山松林生物量和碳储量总体呈上升的趋势,不同的生物量与碳储量结论源于数据库基础数据的差异与统计方法不同。     

广州市森林生态系统碳储量格局分析

相对准确地计量地带性森林碳库大小是估算区域森林碳汇潜力的前提。根据全市不同森林类型设置样地900个,运用样地清查法估算广州市森林生态系统碳储量和碳密度。结果表明:广州市森林生态系统碳储量为52.16 Tg C。其中,植被层和土壤层碳储量分别为21.97 Tg C和27.16 Tg C。碳储量空间分布主要集中在从化区和增城区;总碳储量的组成中,土壤层碳库比例最大(58%),其次为乔木层碳库比例(40%),而灌木层、草本层、凋落物层和细根(≤ 2.0 mm)的生物量比例大多在1%~2%;天然林碳储量与人工林接近,但是碳密度显著大于人工林(p < 0.05);不同林龄从小到大排序为:幼龄林、中龄林、近熟林、过熟林、成熟林;天然林以阔叶混和它软阔的碳储量最高,阔叶混和黎蒴的碳密度最高。人工林不同林型从大到小排序为:南洋楹 > 黎蒴 > 木荷 > 木麻黄 > 它软阔 > 阔叶混 > 湿地松。森林生态系统碳密度为178.03 t C hm-2,其中,植被层和土壤层碳密度分别为79.61 t C hm-2和98.42 t C hm-2。本研究全面计量了广州市森林生态系统碳库现状,这对评估该地区森林固碳潜力和指导碳汇林经营管理具有重要参考价值。     

东莞森林生态系统碳储量研究

采用2 km ×2 km的UTM网格取样法对广东省东莞市8个主要森林类型的植被碳库、凋落物碳库和土壤碳库等三大碳库的有机碳储量和碳密度进行了计量、比较分析和评价.结果表明:东莞森林碳储量总量为973.05 ×104 t,森林总平均碳密度为175.86 t·hm-2;其中森林植被总碳储量为161.48 × 104t,平均...     

基于地理加权回归模型的珠三角森林碳储量空间分布

森林碳储量是研究森林生态系统功能的重要指标,同时也是人们经营森林的参考。珠三角为国内重要的发达地区,研究其森林碳储量分布格局,可以为珠三角森林城市群建设提供重要的理论依据。为精准估测大尺度森林碳储量空间分布格局,以2017年珠三角区域419块森林资源连续清查样地数据为研究对象,采用普通最小二乘法(OLS)模型和4种地理加权回归(GWR)模型对珠三角森林碳储量进行空间分布预测。结果表明：4种GWR模型均比OLS模型有更好的拟合效果和独立性样本检验结果,其中MGWR(Gaussian)的模型拟合效果最佳,GWR(Gaussian)的独立性样本检验结果最佳;运用GWR(Gaussian)模型估测的珠三角森林单位面积碳储量为6.15～81.52 t/hm²,平均值为33.46 t/hm²,且估测误差优于OLS模型,整体上呈现中心高、边缘低的空间分布格局。地理加权回归方法能较有效地估测森林碳储量,并且通过调整模型形式和空间核函数可进一步提高估测精度,为珠三角森林碳储量估测提供了新的方法和思路。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.