A model of carbon storage in forests and forest products

This paper discusses the general formulation of a model that describes carbon storage in a forest and its timber products as a function of the forest growth curve, the rotation period and the carbon retention curves for the timber products. After a number of rotations, the rotation-averaged quantity of stored carbon approaches an asymptotic value. It is shown that, when forests are managed for maximum sustained yield of biomass, the contribution to asymptotic carbon storage from timber products is about 2.5D/T* times the contribution from living trees, where D is the characteristic decay time for reconversion of timber products to carbon dioxide, and T* is the normal rotation period for maximum sustained yield. For a given value of D/T*, carbon storage can be optimized if the policy of maximizing sustained yield is relaxed. For D/T* < 1, as the rotation period is increased indefinitely, the asymptotic level of carbon storage increases monotonically toward the value of the carbon content of living trees at maturity, g(f). For D/T* > 1, there is a finite, optimal rotation period, T(o), greater than T*, for which asymptotic carbon storage is greater than g(f). As D/T* tends to large values, however, T(o) tends to T*, so that, in this limit, management for maximum sustained yield also ensures maximum carbon storage. From initial planting, the time taken to reach asymptotic carbon storage decreases as the normal rotation period, T*, decreases, but increases almost linearly with increasing decay time of timber products, D. This result qualifies the short-term value of any particular planting strategy.     

湖南碳汇项目林主要建群种生物量模型构建

根据湖南碳汇项目林主要类型,充分利用"八五"-"十二五"期间课题组自有成果,同时开展补充调查,以项目林28个主要建群种为研究对象,依据立地条件、林分类型、群落结构、林龄等因素综合布设386个固定样地,按径阶组分不同的树高级选取目标径阶标准样木2 139株,实测标准木生物量,利用11种形式的生物量模型分别对各树种单株生物量进行拟合,得出拟合效果最优的单株生物量模型,通过评价与检验,各模型均具有较好的拟合精度和预估水平。     

The effect of geographical variation of planting rate on the uptake of carbon by new forests of Great Britain

The planting rates from 1921 to 1996 of new coniferous and broadleavedforests for 11 regions of Great Britain were assembled for thestate and private sectors. Over that period new planting totalled231 kha of conifers and 132 kha of broadleaves in England, 141kha of conifers and 16 kha of broadleaves in Wales and 881 khaof conifers and 52 kha of broadleaves in Scotland. These time series and regional values of Yield Class were usedas input data for an accounting model of carbon in the trees,litter, soils and products to produce estimates of their netuptake of carbon by the forests from the atmosphere (i.e. increasein the carbon pools). On the assumption that conifer and broadleafplanting could be represented by Sitka spruce and beech treesrespectively, litter and forest soil in Great Britain were accumulatingcarbon at 2.42 Mt a^–1 in 1995–96. Coniferous forestaccounted for 89 per cent of this uptake. Scottish conifer andbroadleaf forests took up 68 per cent and mapping the uptakeshowed that the greatest rate occurred in western Scotland.The pool of carbon in wood products increased in 1995–96by 0.31 Mt a_–1. The estimated uptake rates were sensitive to the relative amountsof conifer and broadleaf forest planted (particularly in relationto increases in the pool of carbon in wood products) but notto regional differences in Yield Class. Use of any single YieldClass in the range 10–16 m³ ha^–1 a^–1 for allSitka spruce planting produced estimates of uptake rate in GreatBritain to trees, litter and soil within ±10 per centof that, assuming yield varied across the country. Lack of preciseknowledge on the parameters of the model was estimated to introducean uncertainty of ±30–70 per cent into estimatesof carbon uptake.     

Strategy for implementing silvicultural practices in Japanese plantation forests to meet a carbon sequestration goal

The strategy for implementing silvicultural practices in Japanese plantation forests was examined to achieve a carbon uptake of 13.0 Mt-C year^–1, which was capped by the Marrakesh Accords, during the first commitment period, 2008–2012. The plantation forests that implemented silvicultural practices in the period 1990–2012 (FM plantation forests) were identified in compliance with the hypothesized identification rules, and carbon uptake in the forests was estimated using a simple model composed of simulation and optimization components on the assumption that whole plantation forest is classified into only two groups. Furthermore, parametric analysis was conducted to investigate the relationships among three factors: (1) the average annual harvesting volume (including thinning) in plantation forests during the first commitment period, (2) the total area of FM plantation forests in 2012, and (3) the average annual amount of carbon to be sequestered in FM plantation forests during the first commitment period. The results imply that young stands have to be prioritized in implementing silvicultural practices under any harvesting plan and carbon sequestration goal, and that FM plantation forests sequestered 8.0–10.5 (Mt-C year^–1) carbon in inverse proportion to the harvesting volume of 21.0–14.0 million m³ year^–1 (log volume), assuming that most of the plantation forests were incorporated into them.     

Restoration of floodplain forests in Britain

Floodplain forests have almost completely disappeared from Britain.Throughout the temperate regions of Europe and North Americathey have been greatly reduced and many of the remainder arethreatened. River control has altered the natural flooding anddisturbance regime. However, changes in agricultural requirementsand attitudes to river management and the need to improve waterquality have created an opportunity for restoring some morenatural river dynamics and habitats. This paper presents a casefor including managed and natural floodplain forests in riverand floodplain restoration projects. Benefits would accrue fortimber production, reduction of agricultural surpluses, natureconservation, fishing, water quality, river control and landscapequality. Limited practical experience of floodplain forest restorationin North America and continental Europe suggests that practicalproblems can be overcome.     

Rationale and methods for conserving biodiversity in plantation forests

Industrial forest managers and conservation biologists agree on at least two things: (1) plantation forests can play a role in conserving biodiversity, and (2) plantations will occupy an increasing proportion of future landscapes. I review literature from around the world on the relationship between biodiversity and plantation management, structure, and yield. The dynamics of plantation ecology and management necessarily differ by landscape, geographic area, ecosystem type, etc. This review provides a broad array of management recommendations, most of which apply to most regions, and many patterns are evident. I suggest a new plantation forest paradigm based on the hypothesis that minor improvements in design and management can better conserve biodiversity, often with little or no reduction in fiber production. There is ample evidence that these methods do benefit biodiversity, and can also entail various economic benefits. Adherence to these recommendations should vary by plantation type, and depending on the proportion of the surrounding landscape or region that is or will be planted. Stand-level variables to consider include socio-economic factors, native community type and structure, crop species composition, and pest dynamics. During establishment, managers should consider innovations in snag and reserve tree management (e.g. leave strips), where mature native trees and/or understory vegetation are left unharvested or allowed to regenerate. Polycultures should be favored over monocultures by planting multiple crop species and/or leaving some native trees unharvested. Native species should generally be favored over exotics. Site-preparation should favor methods that reflect natural disturbances and conserve coarse woody debris. Plantations that have already been established by traditional design can also conserve biodiversity via small modifications to operations. Earlier thinning schedules or longer rotations can strongly affect biodiversity, as can reserve trees left after plantation harvest to remain through a second rotation.     

伊春林区宣贯国家原木标准情况的调查分析

过去，由于领导质量意识差，质检人员素质低，制度不健全，使得山中楞造材质量问题严重，贮木场质量问题普遍存在，管理不适应，造成资源浪费，效益流失，产品滞销。因此建议：推行ISO9000认证；按市场需求组织生产；加大标准化执法力度；建立激励机制。     

Relationships between insect diversity and habitat characteristics in plantation forests

A methodological approach to the identification of biodiversity indicators in commercial forest stands is illustrated by analysis of the relationships between syrphid (hoverflies) and carabid (ground beetles) community composition and diversity, and stand structure and field layer vegetation. Data were collected from 12 commercial forest sites encompassing a range of climatic conditions and different crop types (Scots pine, Sitka spruce, Norway spruce and Corsican pine) across the UK. Comparisons were also made between unmanaged semi-natural Scots pine woods and Scots pine plantations. For both syrphids and carabids, no differences in species richness and diversity were recorded between semi-natural stands and plantations; one rare syrphid considered to be restricted to semi-natural pine stands was also found in spruce. Syrphid species diversity and richness was higher in southern spruce sites than in the northern sites. Northern sites had distinctive carabid communities, as did sites in the New Forest, a large ancient woodland in southern England. Of the measured habitat variables, vertical stand structure showed the best correlation with species richness and diversity of both carabids and syrphids. Richness and diversity were less in stands with high vertical cover values for canopy layers. Stands with higher field layer cover supported greater syrphid diversity, but lower carabid diversity. Measures of stand structure could be used as potential indicators of syrphid and carabid diversity, but additional habitat parameters also need to be tested.     

推进碳汇林业发展的几点思考

本文结合吉林省实际,重点阐述了碳汇林业发展的必要性和重要性,指出了科技、人才对碳汇林业发展的支撑作用,强调了科技研发环节前移和发挥学术组织作用的战略选择。     

阿尔山林区人工林经营中存在的问题及对策

本文根据阿尔山林区实际情况，分析了阿尔山林区人工林生长规律及经营中存在的问题，并针对存在的问题，提出对策。     

论人工林对解决木材供需及环境的影响

本文结合世界人工林发展的趋势，阐述了发展人工林对缓解林产品需求及环境保护的重要性，论述发展人工林带来的经济、社会效益。     

Tropical reptiles in pine forests: Assemblage responses to plantations and plantation management by burning

Worldwide, the land area devoted to timber plantations is expanding rapidly, especially in the tropics, where reptile diversity is high. The impacts of plantation forestry and its management on native species are poorly known, but are important, because plantation management goals often include protecting biodiversity. We examined the impact of pine (Pinus caribaea) plantations, and their management by fire, on the abundance and richness of reptiles, a significant proportion of the native biodiversity in tropical northern Australia, by (i) comparing abundance and diversity of reptiles among pine plantations (on land cleared specifically for plantation establishment), and two adjacent native forest types, eucalypt and Melaleuca woodlands, and (ii) comparing reptile abundance and richness in pine forest burnt one year prior to the study to remove understorey vegetation with pine forest burnt two years prior to the study. We also examined the influence of fire on reptile assemblages in native vegetation, by comparing eucalypt woodland burnt two years prior to the study and unburnt for eight years. To quantify mechanisms driving differences in reptile richness and abundance among forest types and management regimes, we measured forest structure, the temperatures used by reptiles (operative temperature) and solar radiation, at replicate sites in all forest types and management regimes. Compared to native forests, pine forests had taller trees, lower shrub cover in the understorey, more and deeper exotic litter (other than pine), and were cooler and shadier. Reptile assemblages in pine forests were as rich as those in native forests, but pine assemblages were composed mainly of species that typically use closed-canopy rainforest and prefer cooler, shadier habitats. Burning did not appear to influence the assemblage structure of reptiles in native forest, but burning under pine was associated with increased skink abundance and species richness. Burned pine was not warmer or sunnier than unburned pine, a common driver of reptile abundance, so the shift in lizard use after burning may have been driven by structural differences in understorey vegetation, especially amounts of non-native litter, which were reduced by burning. Thus, burning for management under pine increased the abundance and richness of lizard assemblages using pine. Pine plantations do not support the snake diversity common to sclerophyllous native forests, but pine may have the potential to complement rainforest lizard diversity if appropriately managed.     

A novel approach to optimize management strategies for carbon stored in both forests and wood products

We present a new approach to maximize carbon (C) storage in both forest and wood products using optimization within a forest management model (Remsoft Spatial Planning System). This method was used to evaluate four alternative objective functions, to maximize: (a) volume harvested, (b) wood product C storage, (c) forest C storage, and (d) C storage in the forest and products, over 300 years for a 30,000 ha hypothetical forest in New Brunswick, Canada. Effects of three initial forest age-structures and a range of product substitution rates were tested. Results showed that in many cases, C storage in product pools (especially in landfills) plus on-site forest C was equivalent to forest C storage resulting from reduced harvest. In other words, accounting for only forest, and not products and landfill C, underestimates true forest contributions to C sequestration, and may result in spurious C maximization strategies. The scenario to maximize harvest resulted in mean harvest for years 1–200 of 3.16 m³ ha⁻¹ yr⁻¹ and total C sequestration of 0.126 t ha⁻¹ yr⁻¹, versus 0.98 m³ ha⁻¹ yr⁻¹ and 0.228 t ha⁻¹ yr⁻¹ for a scenario to maximize forest C. When maximizing total (forest + products) C, mean harvest and total C storage for years 1–200 was 173% and 5% higher, respectively, than when maximizing forest C; and 218% and 6% higher, respectively, when maximizing substitution benefits (0.25 t of avoided C emissions per m³ of lumber used) in addition to total C. Initial forest age-structure affected harvest in years 1–50 < 34% among the four alternative management objective scenarios, and resulted in mean C sequestration rates of 0.31, 0.10, and −0.14 t ha⁻¹ yr⁻¹ when maximizing total C storage for young, even-aged, and old forests, respectively. Our results reinforce the importance of including products in forest-sector C budgets, and demonstrate how including product C in management can maximize forest contributions toward reduced atmospheric CO₂ at operational scales.     

Carbon stocks and sequestration in plantation forests in the Republic of Ireland

The United Nations Framework Convention on Climate Change andits Kyoto Protocol (KP) have created a clear need for methodsthat enable accurate accounting of carbon (C) stocks and stockchanges in forest ecosystems. The rate of accumulation of Cin plantation forests in the Republic of Ireland was estimatedfor the period 1906–2002 using the record of afforestationand a dynamic C accounting model (C-flow). Projections for theperiod 2003–2012 were made using different afforestationrates. It was assumed that Sitka spruce planted in the period1906–1989 was Yield Class (YC) 16 m³ ha^–1 year^–1and that after 1990 this increased to 20 m³ ha^–1 year^–1.All other conifers were assumed to have the growth characteristicsof YC 8 m³ ha^–1 year^–1 lodgepole pine. Broadleaveswere assumed to have the growth characteristics of YC 6 m³ ha^–1year^–1 beech. In 2002, the total forest C stock was 37.7Mt C representing an increase of 14.8 Mt C since 1990. In 2002,the rate of increase in trees, products, litter and soil was0.7, 0.1, 0.1 and 0.5 Mt C, respectively. Under a business-as-usualscenario, afforestation since 1990 is estimated to create anannual average C sink of 0.9 Mt C year^–1 during the period2008–2012. This accounts for 22 per cent of Ireland'sreduction commitment under the KP. Afforestation on peat soilswas found to reduce the net C sink, although the extent to whichit does so is highly dependent on assumptions regarding therate of peat C loss.     

Identifying factors affecting plantation performance in boreal forests of Ontario

Plantation data from northern Ontario were subjected to stepwise regression analysis to express survival and total height as functions of site factors, planting stock characteristics and age for each of black spruce (Picea mariana [Mill.] B.S.P.), white spruce (P. glauca [Moench] Voss) and jack pine (Pinus banksiana Lamb.).Total height and height increment were affected more significantly, but by fewer factors, than survival. Black spruce survival was the most heterogeneous variable, as six factors accounted for 55.6% of its variability. Between one and five qualitative site factors (represented by dummy variables) accounted for less than 23% and 30%, respectively, of the variability in survival rate and total height. Stock type, planting season, weed control and chemical site preparation showed low but significant correlations with the response variables. Quality index was significant in every case, while shoot:root ratio, root collar diameter and dry weight were significant in some cases. The single most significant variable was plantation age, accounting for up to 30% and 63%, respectively, of the variability in survival rate and total height.     

木炭的土地利用及碳汇效应

在土壤中施入木炭颗粒,不仅能提高土壤的透气、透水、保水性能,提高土地的生产力及产品的品质,而且阻断了木炭本身成为碳源的通道。同时,通过提高植物的生长量,可更多地吸收大气中的CO2,提高碳汇效应。     

Assessing carbon sequestration in plantation forests of important conifers based on the system of permanent sample plots across Taiwan

ABSTRACT

Plantation forests play a critical role in forest management due to their high productivity and large contribution to carbon sequestration (CSE). The purpose of this study was to assess the CSE of plantations containing four important conifer species distributed across Taiwan, namely, the China fir (Cunninghamia lanceolata), Japanese cedar (Cryptomeria japonica), Taiwania (Taiwania cryptomerioides) and Taiwan red cypress (Chamaecyparis formosensis). Data regarding the plantations were obtained from a survey of permanent sample plots (PSPs). We used these data to calculate the CSE in each PSP and adopted CSE_mean and CSE_period as indicators to assess the CSE of the four conifers. According to the CSE_mean obtained from analysis of variance and the least significant difference method, two groups were identified among these four conifers: the Japanese cedar (4.03 Mg ha^?1 yr^?1) and Taiwania (3.52 Mg ha^?1 yr^?1) yielded higher CSE_mean values and the China fir (1.79 Mg ha^?1 yr^?1) and Taiwan red cypress (2.36 Mg ha^?1 yr^?1) yielded lower CSE_mean values. The same patterns were observed in the CSE_period values; however, no significant difference in CSE_period was observed between Taiwan red cypress and either of the two groups. Therefore, Japanese cedar and Taiwania have high CSE potential among conifers.     

贵州省森林碳汇及潜力分析

区域层面的森林碳汇估算研究有利于为整体层面持续固碳增汇的森林经营提供科学参考,评估森林碳汇对减少区域内碳排放的贡献。采用温室气体清单估算法,对2000、2005和2010年贵州省森林碳汇进行估算,分别为1 538.0万t、2 244.7万t、2 431.4万t CO2当量,呈稳定增长趋势,占全省碳排放量的10.32%～14.47%。贵州省尚有161.70万hm2宜林地,如果能用于发展碳汇林业,每年可吸收CO2237.9万t,30年内将吸收CO2达7137.0万t。贵州省正处于碳排放增长阶段,相对于森林碳汇而言,本区域碳减排工作任重道远,森林碳汇能力有很大的提升空间。     

The impact of nitrogen deposition on carbon sequestration by European forests and heathlands

In this study, we present estimated ranges in carbon (C) sequestration per kg nitrogen (N) addition in above-ground biomass and in soil organic matter for forests and heathlands, based on: (i) empirical relations between spatial patterns of carbon uptake and influencing environmental factors including nitrogen deposition (forests only), (ii) ¹⁵N field experiments, (iii) long-term low-dose N fertilizer experiments and (iv) results from ecosystem models. The results of the various studies are in close agreement and show that above-ground accumulation of carbon in forests is generally within the range 15–40 kg C/kg N. For heathlands, a range of 5–15 kg C/kg N has been observed based on low-dose N fertilizer experiments. The uncertainty in C sequestration per kg N addition in soils is larger than for above-ground biomass and varies on average between 5 and 35 kg C/kg N for both forests and heathlands. All together these data indicate a total carbon sequestration range of 5–75 kg C/kg N deposition for forest and heathlands, with a most common range of 20–40 kg C/kg N. Results cannot be extrapolated to systems with very high N inputs, nor to other ecosystems, such as peatlands, where the impact of N is much more variable, and may range from C sequestration to C losses.