Above-ground biomass dynamics after reduced-impact logging in the Eastern Amazon

Changes in above-ground biomass (AGB) of 17 1 ha logged plots of terra firme rain forest in the eastern Amazon (Brazil, Paragominas) were monitored for four years (2004–2008) after reduced-impact logging. Over the same time period, we also monitored two 0.5 ha plots in adjacent unlogged forest. While AGB in the control plots changed little over the observation period (increased on average 1.4 Mg ha⁻¹), logging resulted in immediate reductions in ABG that averaged 94.5 Mg ha⁻¹ (±42.0), which represented 23% of the 410 Mg ha⁻¹ (±64.9) present just prior to harvesting. Felled trees (dbh > 55 cm) accounted for 73% (±15) of these immediate losses but only 18.9 Mg ha⁻¹ (±8.1) of biomass was removed in the extracted logs. During the first year after logging, the annual AGB balance (annual AGB gain by recruitment and growth − annual AGB loss by mortality) remained negative (−31.1 Mg ha⁻¹ year⁻¹; ±16.7), mainly due to continued high mortality rates of damaged trees. During the following three years (2005–2008), average net AGB accumulation in the logged plots was 2.6 Mg ha⁻¹ year⁻¹ (±4.6). Post-logging biomass recovery was mostly through growth (4.3 ± 1.5 Mg ha⁻¹ year⁻¹ for 2004–2005 and 6.8 ± 0.9 Mg ha⁻¹ year⁻¹ for 2005–2008), particularly of large trees. In contrast, tree recruitment contributed little to the observed increases in AGB (1.1 ± 0.6 Mg ha⁻¹ year⁻¹ for 2004–2005 and 3.1 ± 1.3 Mg ha⁻¹ year⁻¹ for 2005–2008). Plots with the lowest residual basal area after logging generally continued to lose more large trees (dbh ≥70 cm), and consequently showed the greatest AGB losses and the slowest overall AGB gains. If 100% AGB recovery is desired and the 30-year minimum cutting cycle defined by Brazilian law is adhered to, current logging intensities (6 trees ha⁻¹) need to be reduced by 40–50%. Such a reduction in logging intensity will reduce financial incomes to loggers, but might be compensated for by the payment of environmental services through the proposed REDD (reduced emissions from deforestation and forest degradation) mechanism of the United Nations Framework Convention on Climate Change.     

Property rights,land conflicts and deforestation in the Eastern Amazon

In the Brazilian Amazon, insecure property rights are among the main causes of land conflicts and deforestation. Through an in-depth empirical case study in Maranhao in the Eastern Amazon, this research analyzes how distorted agrarian, forest and environmental policies, laws and regulations originated insecure property rights not only over land, but also over timber, which allied to social and political factors, such as uneven distribution of land and strong organization of landless peasants, led to land conflicts and deforestation. This paper also shows that the causes of and the several actors involved in the deforestation of the Amazon were not independent, rather they were related and interact to each other. Compatibility between environmental goals and agrarian policies, regulations and laws are necessary to provide secure and clear property rights to allow a better enforcement of environmental regulations and to give actors incentives to avoid deforestation.     

Agroforestry systems recover tree carbon stock faster than natural succession in Eastern Amazon,Brazil

Agroforestry Systems - The potential of agroforestry systems (AFS) for atmospheric carbon sequestration in degraded tropical lands is of key interest for climate change and rural development...     

Ecological aspects of site recovery under swidden-fallow management in the Peruvian Amazon

The ecological importance of fallowing to swidden (slash and burn) agriculture is well known. Cyclic agroforestry systems which emphasize utilization of the fallow cycle should, where appropriate, consider the ecologic processess of site recovery, so as not to impair the productivity of the subsequent swidden cycle. this artical discusses the ecologic ‘fit’ of a cyclic swidden-fallow management scheme into swidden cultivation and fallow succession. Such a fit suggests a reciprocally reinforcing situation between this agroforestry design and processes involved in site recovery. Observed among some indigenous and colonist inhabitants of the Peruvian Amazon, this system produces fallow crops and products, while enhancing site nutrient recovery. The economic benefits of this scheme have recently been reported (Denevan and Padoch, n.d.) while the ecologic attributes involved in promoting site recovery have not; primarily these include:

1. Less destruction of the nutrient cycling root-mat in the swidden cycle, and its quicker re-formation in the fallow cycle.
2. Discouraging the establishment of exotic, pantropical weeds and grasses such as imperata, while encouraging the colonization of local, early successional species.
3. Encouraging the earlier establishment of woody plants in abandoned swiddens.
4. A natural litterfall higher in nutrients than in unmanaged fallows.
5. Additions of ‘slash’ litterfall higher in nutrient content than natural litterfall in the proximity of valuable managed plants.
6. The increased capacity of the managed stand to scavenge limiting nutrients such as N and P from, and leach unneeded quantities of non-limiting nutrients such as K, Ca and Mg to, thoughfall.
7. Increasing the alkalinity of throughfall, possibly resulting in less soil cation leaching in managed fallows.
8. Staggering seed production, germination and maturation times of the rapid nutrient sycling softwood trees.
9. Increasing the spontaneously occuring abundance of valuable fallow plants with management of successive fallow cycles, thereby possibly reducing the labor requirement, and increasing the value of this agroforestry scheme over time.

     

Grievances,agency and the absence of conflict: The new Suzano pulp investment in the Eastern Amazon

In November 2013, Suzano Papel e Celulose, a Brazilian paper company, is projected to inaugurate the world's largest pulp mill in Imperatriz in the remote state of Maranhão, Eastern Amazon. This investment will further consolidate Brazil's position as the leading exporter of wood-pulp coming from vast, corporate-controlled industrial plantations. These inland forestry investments are a feature of the second wave of large pulp projects, extending inland from the best lands in the coastal belt via accessible rivers and railroad networks. This globally significant inland expansion has been poorly studied, if at all. No publications exist on this Suzano pulp project. Empirically, this article provides a baseline study on the political economic dynamics.The case is highly relevant for conflict theory. Generally, industrial tree plantation expansion has boosted grievances, but the resistance and conflicts have varied depending on the social actors' agency. In comparison to the high-intensity conflicts between the rural social movements such as the Brazilian Landless Movement (MST) and the pulp companies in most other new investments, there has been a rare absence of conflict in this case, as no movement has seized on local grievances. Conflicts cannot be studied in-depth by focusing only on conflict cases. Absence-cases open up an opportunity to revisit the question why conflicts arise. An analysis of this case allows an empirically rooted theoretical discussion on conflict causalities, which can answer several vexing questions in the study of conflicts. A new and generally applicable typology of different types of grievances is offered, and the grievances' causal relation to conflicts is examined. The importance of political dynamics and inter-personal relations in investment conflicts is emphasized. The way culture influences conflict dynamics is pondered upon by ethnography of the Brazilian conflict culture, where personal relations are more relevant in explaining conflict escalation than in the political systems with a stronger (impersonal) rule of law. The role of third parties such as other industries in the investment area is discussed. A qualitative comparative analysis of the major pulp project conflicts and their causes in Latin America is offered. Mobilization and thus conflict causality is explainable only when taking into account the types of grievances and the local, inter-personal, and organizational (state–business–movement) relations by which these are remediated and negotiated.     

桂东地区马尾松林下种植金花茶密度控制研究

为解决金花茶(Camellia nitidissima)产品原料短缺问题,提高马尾松林(Pinus massoniana)地利用率和产出率,于2014年6月至2016年5月在桂东岑溪市紫胶林场开展了马尾松密度×金花茶密度双因素随机区组试验。研究结果表明:金花茶造林适合的株数密度随马尾松株数密度递增呈增大的趋势,300株/hm~2(郁闭度0.4~0.45)马尾松林下适合种植金花茶密度要控制在1 665株/hm~2以下,450株/hm~2(郁闭度0.5~0.6)马尾松林下适合种植金花茶密度控制在1 665~2 505株/hm~2,600株/hm~2(0.6~0.7)马尾松林下适合种植金花茶密度控制在2 505~3 330株/hm~2;金花茶生长区组间的差异达到显著水平,位于中坡金花茶要比上坡金花茶生长好;在桂东地区12月至次年2月金花茶生长基本停滞,金花茶施肥适宜安排在3-9月。     

湘东常绿阔叶林林内景观质量评价与分析

以位于湘东的浏阳大围山国家森林公园阔叶林的林内景观为研究对象,从所拍摄的照片中选取了45张最具代表性的,采用SBE评价法对景观的质量进行评价。把林内景观分解为13个要素,每个要素设置3~4个类目,共计39个景观要素组合。通过相关性分析和归回分析,剔除了相关性小的要素,保留了6个相关性较大的要素。结果表明,林内景观要素对美景度的贡献率依次为平均树高(27.7%)、平均胸径(20.2%)、林分密度(17.3%)、色彩丰富度(16.4%)、枯树倒木(9.4%)、绿视率(9.0%),据此建立了景观美学质量与各景观因子类目之间的多元回归模型。提出了修枝、调整林分密度、清理枯倒断木、增加地被植物等提质改造措施。     

湖南省退耕还林工程生态效益评价

通过对2006年湖南省退耕还林工程的保水效益、固土保肥效益、固碳制氧效益、生物多样性效益进行价值计量与评估,结果表明:2006年湖南省退耕还林工程生态效益价值为523 495.69万元。其中:固碳制氧价值为261 204.54万元,占总值的49.9%;生物多样性价值为133 923.41万元,占总值的25.58%;固土保肥价值为98 880.74万元,占总值的18.89%;森林保水价值为29 487.00万元,占总值的5.63%。     

青海东部干旱区甘蒙锦鸡儿效益评价

甘蒙锦鸡儿(Caragana opulens Kom.)是青海省浅山地区干旱阳坡广泛分布的一种抗逆性强的乡土树种.本研究表明,其在青海恶劣环境中所起的生态作用远大于其自身的经济价值,该树种林地的改土、蓄水、保土效益显著,是极优良的水土保持灌木树种,在用作薪材、饲料、肥料及其它民用材料方面也有较高的实用价值.     

辽东山区柞树林不同间伐强度下物种多样性分析

物种多样性是描述森林群落结构及个体组成的一个重要指标。采用Margalef丰富度指数、ShannonWiener多样性指数、Simpson多样性指数、Pielou均匀度指数等几个主要参数对辽宁东部山区柞树林不同间伐强度下植物种类多样性规律进行了研究。结果表明,随着柞树林间伐强度的递增,群落的多样性呈递减的趋势。     

辽东地区红松人工林不同间伐强度下生物多样性研究

以辽东红松人工林为对象,研究了不同间伐强度下该林型的生物多样性。研究结果表明:间伐后,红松人工林内双子叶植物的种类都大于单子叶植物,红松人工林对照区中单子叶植物科的数量最小,其他3个区随间伐强度增大单子叶植物科的数量增多。红松人工林对照区的双子叶植物属数最小;弱度区、中度区、强度区三区随间伐强度增大,属数依次减小,但都高于对照区。蕨类植物在红松人工林内虽出现但数量很少。裸子植物在红松人工林内未出现。红松人工林的草本多样性以弱度区最高,弱度区与强度区相近。红松的灌木多样性差别不大。     

基于GIS的四川省中东部生态风险评价

随着自然灾害的增加,生态风险评价的重要性凸显。本文以四川省东部为例,以人口、土地类型、气候、植被等数据为基础,构建了生态系统脆弱性指数,利用地理信息系统空间分析方法对四川省中东部的生态脆弱性状况进行分析,从而评价该区域的生态风险。旨在揭示人类活动对生态环境的影响程度,从而为区域生态保护决策提供可靠的依据。结果表明:研究区域生态风险的空间分布表现出明显的区域差异,成都和区域的中心城市所在地区生态风险指数较高,遂宁和内江西部地区生态风险指数较低,而其他地区的生态风险指数处于过渡区域。     

Harvesting intensity versus sustainability in Indonesia

In East Kalimantan (Indonesia), impacts of conventional (CNV) and reduced-impact logging (RIL) on forest ecosystems were compared on the basis of pre- and post-harvesting stand inventories. There was a positive and significant correlation between the proportion of trees damaged by felling and the density of trees felled. Logging intensity ranged from 1 to 17 trees ha⁻¹(9–247 m³ ha⁻¹) and averaged 9 trees ha⁻¹ (86.9 m³ ha⁻¹). The study has shown that with RIL techniques, logging damage on the original stand can be significantly reduced by 50% compared with conventional logging. However, this 50% reduction in logging damage, was dependent on the felling intensity. With a felling intensity of 8 stems ha⁻¹ or less, RIL techniques only damaged 25% of the original tree population whereas 48% were damaged with conventional techniques. Above this felling intensity (i.e. 8 stems ha⁻¹), the effectiveness of RIL in limiting forest damage was significantly reduced, mainly because of the increasing felling damage. Moreover, the removal of all harvestable timber trees, leaving only few potential crop trees, will result in a seriously depleted residual stand. Because of the high damage involved by high felling intensity, leaving few potential crop trees, and the yield capacity of the remaining stand, acceptable harvesting volume will not be reached within the felling rotation of 35 years. It is concluded that silvicultural system based on diameter limit alone, as is the Indonesian system (TPTI), cannot be compatible with sustainability and more sophisticated harvested-selection rules are needed.     

粤东滨海城市绿化树种抗风性评价与筛选

在地处广东省沿海的汕头市市区设置固定风口调查小区,分别在2003年第13号台风"杜鹃"、2005年第10号强热带风暴"珊瑚"、2006年第1号强台风"珍珠"过后进行绿化树种风害调查;以灾后风害木恢复原景观的修复投入比例综合专家咨询确定权重,采用改良加权评分法分析城市绿化树种的抗风性,结果表明:汕头市区66个常见绿化树种,可以划分为4个抗风级别,其中Ⅰ级树种36个,抗风性较强;Ⅱ级树种19个,抗风性一般;Ⅲ级树种7个,抗风性较差;Ⅳ级树种4个,不抗风.     

大兴安岭东部林区植被蓄水潜力与价值的评估

以中国植被1:100万植被图为基础,收集了各种植被类型冠层降水截留量、枯落物现存量和土壤非毛管孔隙度的数据和资料,将大兴安岭东部林区主要植被类型归并为9类,对这些主要植被类型对降水的分配和贮存进行了综合评价,并研究了大兴安岭地区植被蓄水潜力及其价值的空间分布特征.结果表明:大兴安岭原生植被中,以蒙古栎为优势种的落叶阔叶林、云冷杉林和兴安落叶松林具有较强的持水能力.兴安落叶松林分布面积广,蓄水潜力占全区水源涵养价值的58.4%.从区域分布来看,水源涵养能力强的植被主要分布在该区的东南部.为了防止本区植被水源涵养能力的衰退,需要控制采伐,加强天然林保护,同时要加强护林防火工作,防止森林向山地杨桦林、疏林和低效林退化.     

Five native tree species and manioc under slash-and-mulch agroforestry in the eastern Amazon of Brazil: plant growth and soil responses

Throughout the Amazon of Brazil, manioc (Manihot esculenta) is a staple crop produced through slash-and-burn agriculture. Nutrient losses during slash-and-burn can be large and nutrient demand by food crops so great that fields are often abandoned after two years. In recent decades, farmers have reduced the fallow phase from 20 to ~5 years, limiting plant nutrient accumulation to sustain crop yields. Improved fallows through simultaneous planting of trees with food crops may accelerate nutrient re-accumulation. In addition, slash-and-mulch technology may prevent loss of nutrients due to burning and mulch decomposition may serve as a slow-release source of nutrients. This study in Pará, Brazil, in a 7-year-old secondary forest following slashing and mulching of the vegetation, involved two main plot treatments (with and without P and K fertilizers) and two sub-plot treatments (with or without a N₂-fixer Inga edulis). A mixed-culture of trees and manioc was planted in all plots. P and K fertilizer increased tree mortality due to weed competition but growth of surviving trees in four of the five tree species tested also increased as did biomass production of manioc. In the N₂-fixer treatment trends of greater growth and survival of four of five tree species and manioc biomass were also observed. Fertilization increased the biomass of competing vegetation, but there was a fertilizer by N₂-fixer interaction as I. edulis caused a reduction in competing biomass in the fertilized treatment. After one year, fertilization increased decomposition of the mulch such that Ca, Mg, and N contents within the mulch all decreased. In contrast, P and K contents of mulch increased in all treatments. No influence of the N₂-fixer on 0–10 cm soil N contents was observed. Two years after establishment, this agroforestry system succeeded in growing a manioc crop and leaving a well-maintained tree fallow after the crop harvest.     

Evaluation of forestry programs: A case study of the forestry incentives program in Massachusetts

A general methodology is proposed to evaluate forestry programs which are aimed at increasing timber supply from non-industrial private forest lands. A financial analysis of the forestry activities included in the program or a questionnaire submitted to the landowners should serve to establish what would have been done in the absence of the program. An economic analysis aggregating the marginal benefits and costs for each program participant can be related in different benefit—cost ratios.The methodology is applied to the evaluation of the Forestry Incentives Program (FIP) in Massachusetts. The study shows that the efficiency benefit—cost ratio is > 1 at 4% and 6.625% and that the landowner's management decisions are crucial to the performance of the program.     

Evaluation of the performance of the community rainforest reforestation program in North Queensland,Australia

The Community Rainforest Reforestation Program (CRRP) in north Queensland, Australia, was a multi-faceted experiment in facilitating farm forestry. It was motivated in part by the World Heritage listing of the Wet Tropics of Queensland rainforests, which removed a large resource from the timber industry. Survey results indicate that some landholders have applied high-quality silvicultural management to their stands with a view to timber production, while others have been more interested in wildlife habitat and other non-wood benefits. Although not necessarily a success in terms of its stated goals, the program can be credited with a number of achievements. It yielded valuable experience in growing native tree species, job training for young unemployed people, and collaboration between Federal, State and local government in forest industry development. The program generated positive environmental outcomes and lessons for future timber and environmental planting programs on private lands. While the area planted and quantity of timber produced will fall far short of initial expectations, and some limitations arose with the job training activities, it nevertheless appears to have been a worthwhile project.     

Normalization of wood density in biomass estimates of Amazon forests

Wood density is an important variable in estimates of biomass and carbon flux in tropical regions. However, the Amazon region lacks large-scale wood-density datasets that employ a sampling methodology adequate for use in estimates of biomass and carbon emissions. Normalization of the available datasets is needed to avoid bias in estimates that combine previous studies of wood density that used wood sampling at diverse positions in the bole or with various methods of density determination. This paper examines the question of whether regressions for radial variation and for variation in wood density along the bole, both developed in dense forest in central Amazonia (CA), are suitable for the open forests in southern Amazonia (SA) that are currently the target of most of Amazonia's deforestation activity. The wood density of the heartwood and density of full disks or slices (bark, sapwood and heartwood) in each tree were measured to assess the radial variation. For variation along the length of the bole, wood densities at breast height and at the top of the bole were used. Moisture content of the bole was measured in SA and compared with values reported by studies from CA in similar dense forest. Comparing regressions that predict full-disk density from heartwood density, the pattern of radial variation differs slightly and significantly between the two forest types (ANCOVA p = 0.006); the slopes have similar values but the intercepts differ. Variation along the bole in the two forest types does not differ significantly (p = 0.144), so the CA model for predicting mean bole density from the density of a slice at breast height gives an unbiased estimate of the mean bole density when applied to SA trees. In SA the mean moisture content of the bole was 0.416 (±0.068 S.D.; n = 223 trees). Moisture content of the bole had a strong inverse relationship with basic wood density (r = −0.77), which explains the lower moisture content in the trees in CA relative to SA. A much weaker inverse relationship was found between moisture content and green wood density (r = −0.292). The relationship between wood basic density and green (‘fresh’) density presented in this study provides an alternative means of obtaining basic wood density directly in the field when oven drying of samples is not possible.