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1.
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. 相似文献
2.
Possible Impacts of Climatic Warming on Trees and Forests in the United Kingdom: a Review 总被引：2，自引：0，他引：2
There is growing evidence and concern that increasing levelsof greenhouse gases in the atmosphere will increase global temperatures.Temperatures in the UK may increase by 3C± 1.5C overthe next 70 years The tree crop is sensitive to such large andrapid climatic change because of its longevity. This paper reviews(1) changes that might occur in the forest environment, includingsoil, following climatic warming; (2) past and future long-termchanges in the species composition of UK forest; (3) possiblepositive and negative effects.of climatic warming on the growthand yield of UK forests; and (4) the vulnerability of foreststo any change in the frequency of extreme events. 相似文献
3.
Stands of clonal Salix viminalis (in 1985) and Populus trichocarpa(in 1986) were grown for one growing season from cuttings incontainers, at 0.3 m spacing, supplied with trickle irrigationand nutrients. Woody biomass production (Bw) in the first yearwas analysed as the product of the proportion of dry matterpartitioned to wood ({macron}), the seasonal mean efficiencywith which intercepted light was used to produce dry matter({macron}), the mean fraction of incident light interceptedby the canopies (f{macron}), and the amount of incoming solarradiation over the season (A). Thus, Bw = {macron}f{macron}{macron}A. For Salix, Bw=10 t ha–1y–1, while for Populus, Bw= 5 t ha–1y–1, mainly because of differences in{macron} and f{macron}. The Populus partitioned more dry matterto roots (and correspondingly less to stems) and interceptedless light over the growing season. The Salix and Populus cloneshad surprisingly similar ({macron}) values, namely 1. 58 and1. 50 g MJ–1, respectively (based on total dry matterand total solar radiation), which are very like the {macron}values measured on C3 agricultural crops in Britain. Also, theSalix and Populus clones produced canopies with similar lightextinction coefficients and hence similar relationships betweenfractional interception and leaf area index. 相似文献
4.
Oyen Bernt-Havard; Blom Hans H.; Gjerde Ivar; Myking Tor; Saetersdal Magne; Thunes Karl H. 《Forestry》2006,79(3):319-329
Results from a literature review on pinewood ecology, silviculture,genetics, aspects of history and forest resources of Scots pine(Pinus sylvestris L.) in western Norway are presented. The pinewoodscover 40 per cent of the forested land, 0.31 million ha. Duringthe last 75 years, the area has increased by 17 per cent andthe growing stock has risen from 10 to 34 million m3. The impactof man in previous times was very marked, and has had a significantinfluence on the present forest conditions. The pronounced climaticgradients mixed with the topographic variation – fromthe coastal plains via the fjord systems to the high mountains– is reflected in rather steep gradients in the pine forestvegetation. Various floristic elements can be distinguished,from oceanic via the suboceanic in the outer islands to thethermophytic, boreonemoral and boreal elements in the innerfjord districts and valleys. The introduction of spruce (Piceaspp.) plantations on 10–15 per cent of former native pineforests has not negatively affected the bird fauna at the landscapescale. Although not particular species rich, the pine forestsharbour species usually not found in other forest types. Sofar, most work in the field of silviculture and forest ecologyin the pinewoods of West Norway has been in the form of casestudies. Implications of the results for forestry in the regionare briefly discussed. 相似文献
5.
The rate of interest to be used for calculations in forestryunder Danish conditions (3 per cent) has beeen determined asthe long-term effective first mortgage rate (4 per cent) lessthe long-term average inflation (1 per cent) and the averageannual relative rise in prices of forest products ( per cent). A comparison shows that agriculture pays a real net return ofabout 3 per cent (about 3 per cent for larger farms). A comparisonwith the profit on shares seems to show that, according to Danishinvestigations, these yield a real profit of about 4 per cent. The rate of interest in forestry-a very safe type of investment-whichwe have estimated to be about 3 per cent of the market value,seems on the whole to fit well into the general real returnlevel in this country. Similarly the average real interest cost of second mortgageloans has been investigated and proved to be about 4 per cent.For forest owners having bank loans secured by third mortgage,the real interest cost of these is presumably 5 per cent ormore, but varies from person to person. A figure shows real interest costs at various degrees of indebtedness. The majority of Danish forests have a rate of interest of about3 per cent, or sometimes less (this applies to some unencumberedestates). So far, only few larger forests have a rate of interestof about 4 per cent. A rate of 5 per cent or more is mainlyseen in very small forests. 相似文献
6.
The study aimed specifically at investigating if canopy opennesswas a better predictor of the height growth of Norway spruce(Picea abies (L.) Karst.) advance regeneration than overstoreybasal area or overstorey standing volume. In 1990, a field experimentwith 3 x 2 factorial design and two replications (blocks) wasestablished in an uneven-aged Norway spruce forest. Plots hada net plot area of 30 x 30 m, each with a 10-m-wide treatedbuffer zone. Three overstorey density levels retained approximately15, 40 and 70 per cent of the pre-harvest overstorey standingvolume and were allotted to the plots. Two types of thinningthat harvested smaller trees or harvested larger trees wererandomly allocated to each pair of overstorey density plots.In mid-June 2000, canopy openness was estimated from hemisphericalphotographs taken at five marked points in the centre of eachof the plots at 0.9 m from ground to the top of the ‘fish-eye’camera lens. Regression results showed that canopy opennesswas a better predictor of height increments of spruce seedlings(0.1< height < 0.5 m), saplings (0.5 height < 2.0m), and small trees (height 2.0 m, diameter at 1.3 m height< 5 cm) than with overstorey basal area (m2 ha–1) oroverstorey standing volume (m3 ha–1). The height incrementof the spruce advance regeneration was not significantly correlatedto stand basal area or to standing volume. Overstorey basalarea in the net plots was significantly negative (P 0.05) withmean canopy openness estimates, and the r2 value was 0.40. Resultsindicated that basal area was not linearly related to canopyopenness as it increased, which might explain the lack of predictivepower of retained basal area on spruce regeneration height indense stands in boreal Sweden. 相似文献
7.
The effects of the number of chromosome sets on chlorophyllcontent in diploid and tetraploid black wattle were assessedthrough chlorophyll absorbance. Seedlings of 8 months of age,1-year-old trees in polybags and 2-year-old field material wereselected for this investigation. Three families per ploidy levelcomprising of 10 half-sibs per family were used in the analysis.An analysis of variance revealed significant differences (P< 0.05) in chlorophyll absorbance between diploid and tetraploidmaterials ( = 0.375 and = 0.653, respectively). Significantdifferences (P < 0.05) between treatments (seedling, baggedmaterial and field material) within each ploidy level were recorded,where chlorophyll absorbance increased from diploid bagged trees( = 0.343) to seedlings ( = 0.375) to field trees ( = 0.408). Similar significant increases were recordedfor the tetraploid seedlings ( = 0.629) to bagged trees ( = 0.644) to field trees ( = 0.686). Significant differences (P < 0.05) were also recordedbetween genetic lines within both ploidy levels. However, whencomparing families within each ploidy level, with respect totreatment differences, in most cases, two of the three familiesshowed no significant differences (P > 0.05). Within eachfamily, significant differences (P < 0.05) were recordedbetween each of the three treatments tested, with the fieldmaterial consistently having significantly (P < 0.05) greateramounts of chlorophyll. 相似文献
8.
Lindgren P. M. F.; Sullivan T. P.; Sullivan D. S.; Brockley R. P.; Winter R. 《Forestry》2007,80(5):587-611
This study was designed to test the hypothesis that large-scalepre-commercial thinning (PCT) to various stand densities, atages 12–14 years, combined with repeated fertilization,would, over a 10-year treatment period, enhance productivityof lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifoliaEngelm.) crop trees. Study areas were located near Summerland,Kelowna and Williams Lake in south-central British Columbia,Canada. Each study area had nine treatments: four pairs of standsthinned to densities of 250 (very low), 500 (low), 1000 (medium)and 2000 (high) stems ha–1, with one stand of each pairfertilized five times at 2-year intervals, and an unthinnedstand. The very low, low- and medium-density stands were alsopruned to a 3-m lift 5 years after thinning. At the tree level,fertilization treatments significantly increased diameter atbreast height (DBH), basal area (BA) and volume growth and heavyPCT significantly increased DBH and BA growth. Pruning may mitigatesome of the negative stem form and wood quality attributes associatedwith fast-growing trees without adversely affecting stem growth.At the stand level, PCT to very low and low densities significantlydecreased the volume growth compared with high-density stands.The potential beneficial impacts that PCT and repeated fertilizationtreatments have for mitigating timber supply shortfalls, aswell as potentially minimizing crop tree losses due to mountainpine beetle (Dendroctonus ponderosae Hopk.), are also discussed. 相似文献
9.
This paper shows that head fires spread in cribs and in controlledburns in gorse and heather (in the New Forest) at similar rates,R, given by
where is the bulk density of the burnt fuel and U is the wind speed in m/s. Although the values of U were similar, the values of differed by more than an order of magnitude betweenthe two types of fire. The constant of proportionality is roughly0.07 kg/m3 for the wildland fuels and 0.05 kg/m3 for cribs.The similarity of the relationships is perhaps more significantthan the agreement between the coefficients, which appears closerthan it really is since the cribs were drier than the wildlandfuels. Assuming a wind speed of 10 mile/h the constant for theGreat Fire of London (1666) was also about 0.05 kg/m3. A comparison between the flames in the controlled burns anda partly theoretical correlation of flame lengths from burningcribs has been partly successful and the duration of flamingof a piece of fuel has been empirically correlated with moisturecontent, though the general effects of moisture on the rateof spread are not satisfactorily accounted for. The reason forthis and other anomalies is probably the relatively few datafor wildland head fires (ten in all) and the fact that theirfuel composition was not uniform. The author uses many of theresults of the work described in an earlier paper in Forestry(Thomas, 1967) to derive heat balances for head fires and todiscuss the theoretical aspects of the above expression. 相似文献
10.
Observations to follow the development of 2-year-old oak seedlingstook place over a 6-year period at a fenced site within a maturestand of oak in southern England. Bramble and bracken were abundant,but the cover of other species was low. Although seedlings doubledin height, only 13 per cent survived and few were taller thaneither bramble or bracken. The initial number of seedlings wasinversely related to both canopy cover and distance to the nearestparent tree. The final number of seedlings could be predictedfrom the initial percentage covers of bramble and bracken, andeither the overstorey canopy cover or the initial number ofseedlings. The average annual rate of seedling mortality, whichwas 25–50 per cent, was significantly influenced by thevegetation present. Grass was positively related to survivalwhereas there was an inverse relationship with both brambleand bracken cover. Models estimated 80 per cent annual seedlingsurvival at 25 per cent bramble cover but only 50 per cent at60 per cent cover. Although grasses can be competitive species,results indicate that oak seedling establishment may be betterin areas with a ground flora comprising grass. 相似文献
11.
Effect of Desiccation on Water Status and Forest Performance of Bare-rooted Sitka Spruce and Douglas Fir Transplants 总被引：3，自引：0，他引：3
Sitka spruce transplants which had been exposed to drying conditionswere assessed for shoot water potential (), shoot moisture content(MC), water saturation deficit (WSD) and root moisture content(RMC) before forest planting. Exposure for 1 hour 44 minuteshad no effect on subsequent survival or growth, but exposurefor 3 hours 18 minutes reduced survival to 68 per cent aftertwo years and significantly reduced height growth. The damagedplants were clearly distinguished at the time of planting by and RMC but not by MC or WSD. After a range of desiccation treatments, survival was high inSitka spruce unless RMC had fallen below 180 per cent but survivalwas reduced in Douglas fir with smaller reductions in RMC or. During the desiccation treatment, Douglas fir started withand maintained a higher RMC than Sitka spruce and reached lowlevels of less rapidly. The poor performance of desiccatedDouglas fir was therefore not the result of an inability toconserve water. After rewetting for one hour in the dark RMC was restored butnot , and there was no significant effect on survival or growthin either species. It may be possible to devise a method to establish when plantsare in poor condition by direct or indirect measurement of RMC,but high levels of RMC can be misleading if rewetting has occurred. Handling systems which involve brief periods of exposure aretolerable for Sitka spruce but not for Douglas fir, and specialmeasures are justified to ensure that the latter species isnever subjected to root desiccation during handling. 相似文献
12.
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. 相似文献
13.
Efficiency of Tree Crowns and Stemwood Production at Different Canopy Leaf Densities 总被引：2，自引：0，他引：2
Variation in the unit leaf rate in trees, i.e. the weight ofwood increment per unit of leaf area, arises from disproportionatechanges in their rates of net photosynthesis and in the allocationof carbohydrates. Changes in unit leaf rate in response to variationsin canopy density were investigated in a thinning experimentestablished in a 36 year-old Douglas fir forest. Tree growthwas estimated from increment cores and leaf area by linear correlationwith sapwood basal area. Net assimilation and mean growth ofindividual trees expressed as basal area and volume decreasedin direct proportion to increase in canopy density from 3.6to 12.0 m2m–2 of projected leaf area. These relationshipswere linear with multiple correlation coefficients (r2)0.97. Net stand increment, in contrast to unit leaf rate, culminatedas projected leaf area approached 6 m2m–2 and decreasedat the higher canopy densities due to mortality. The approachdeveloped in this paper could be applicable in predicting growthin response to various silvicultural treatments. 相似文献
14.
We studied the effect of afforestation on soil CO2 emissionsin blanket peat. The study sites were as follows: two undrainedblanket peatland sites, six sites which had been drained andafforested 3, 19, 23, 27, 33 and 39 years previously, and twoforest sites which were clearfelled in summer 1996. Soil CO2emissions were measured using the soda-lime method during 13sampling campaigns throughout 1997. Each campaign consistedof two consecutive 24-h measurements. Comparison of the averageannual CO2 emission revealed no clear pattern in relation tosoil type and suggests that afforestation does not always leadto an increase in soil CO2 emissions. In the most recently forestedsite, CO2 emissions were 1.7 t C ha–1 a–1 and drainagehad failed to lower the water-table sufficiently to cause alarge increase in CO2 emissions. In the 19-, 23-, 27- and 33-year-oldsites soil CO2 emissions were 1.0–1.4 t C ha–1 a–1and were similar to, or lower than, levels in the undrainedsites. In the 39-year-old site average CO2 emissions were 2.6t C ha–1 a–1. In the clearfelled sites CO2 emissionswere lower at between 1.4 and 1.6 t C ha–1 a–1.Root respiration appears to account for a large proportion ofCO2 emissions, and blanket peat, despite drainage, is resistantto decay. It is concluded that losses of soil C are compensatedby C uptake by the trees. 相似文献
15.
Zhang Gong; Zeng Guang-Ming; Du Chun-Yan; Jiang Yi-Min; Su Xiao-Kang; Xiang Ren-Jun; Huang Lu; Xu Min; Zhang Chang 《Forestry》2007,80(2):211-221
The chemistry and deposition pattern in bulk precipitation andthroughfall (TF) were examined and evaluated based on the 3-yearobservations in Shaoshan subtropical deciduous-conifer mixedforest in central-south China. The TF chemistry was notablychanged when passing through canopies, which probably was attributedto the dry deposition (DD) on leaf surface and the canopy exchanges.Base cations' (Ca2+, Mg2+ and K+) fluxes were significantlyenriched in TF, in particular for K+. The annual K+ canopy exchangewas 12 times larger than DD, and canopy exchange of Ca2+, Mg2+and K+ was four times as high as the DD. The canopy exchangeof base cations in association with weak acid accounted for28.4 per cent of total leached base cations, which was one ofthe important factors to modify the TF chemistry. 相似文献
16.
《Forestry》1979,52(1):107
David WHITEHEAD 1978 Forestry 51, 137–149. Equation (3)on page 144 should read: 相似文献
17.
The purpose of this study was to predict the likely amounts of carbon sequestration on a national scale for Japan in the Article-3.4
private planted forests of the Kyoto Protocol during the first commitment period. We regarded the planted forests that had
undergone silvicultural practices such as weeding, pruning, and thinning since 1990 as Article-3.4 planted forests in accordance
with the definition given by the Forestry Agency of Japan. Regression models were developed to predict the forest areas that
had undergone silvicultural practices, employing silvicultural subsidies and forest workers' wages as predictor variables.
Then the time series changes in the predictor variables were provided by extending their recent trends, with the result being
that the forest areas that have undergone silvicultural practices were predicted on the basis of the three scenarios of the
variables. Thus, the Article-3.4 forest area was calculated considering overlaps of silvicultural practices over fixed stands,
and the area was converted into the amount of carbon sequestration by multiplying it by coefficients such as a volume table,
biomass expansion factor, and others. The result implied that Article-3.4 private planted forests were expected to sequester
8.16–8.87 Mt-C year−1 during the first commitment period. These amounts cover 63%–68% of the carbon sequestration goal by land-use change and forestry
activities capped under the Marrakesh Accords. To realize this prediction, it is important to provide a sufficient silvicultural
subsidy to last until the end of the first commitment period and to implement silvicultural practices on the forest stands
that have not undergone such practices since 1990. 相似文献
18.
Armillaria ostoyae is an important disease of Pinus pinasterin north-west Spain, which kills trees following a heterogeneousspatial structure. In a progeny trial of P. pinaster seedlings,spatial heterogeneity and autocorrelation of neighbour mortalitycaused by A. ostoyae impeded proper analysis of the diseaseincidence. We used variography and kriging methods to describethe spatial distribution of the infection probability and thegenetic variation of the resistance to A. ostoyae among families.The spatial structure of disease incidence was modelled, andthe probability of survival was corrected by kriging at eachtree location. Cumulative mortality 3 years after planting was65.1 per cent. Significant differences among P. pinaster familiesin terms of mortality to A. ostoyae were found, with low individual(h = 0.08) and moderate family (h = 0.35) heritability estimates. According to a theoretical semivariogram, the patch size ofthe disease incidence was 63 m wide. This is the first timevariography and kriging are used to select P. pinaster resistantto Armillaria root rot. It is concluded that geostatistics providesforest pathologists with a powerful tool for screening resistanttrees in field conditions. 相似文献
19.
The Kyoto Protocol brought a new forest function into focus: forests as carbon sinks. This new forest function may lead to
new conflicts, because on the one hand, Switzerland has decided to account for forest management under Kyoto Protocol (Article
3.4), and on the other hand, Swiss Forestry statistics and the Swiss National Forest Inventory indicate that increasing amounts
of wood are being harvested. This trend seems likely to continue. In this study, we used the empirical forest model MASSIMO
and the soil model YASSO to analyse four different forest management scenarios. These scenarios basically feature different
levels of harvesting frequencies and different rotation length, as well as their impact on regional potentials for carbon
sequestration and harvesting amounts. Results were analysed both for the whole of Switzerland and for two very different regions:
The Swiss Eastern Plateau and the Swiss Eastern Alps. The results indicate that Swiss forests can provide an increasing amount
of harvested wood (+18% in relation to the base year 1996) for approximately 20 years and act as a carbon sink accountable
under the Kyoto Protocol (0.5 million tons carbon per year). The corresponding forest management strategy aims for a sustainable
and harvestable increment and may, therefore, avoid spurious carbon maximization in forests that can happen by accounting
for only forest systems, and not for the effect of substitution of non-wood products and fossil fuels by forest products.
The regional results indicate that (1) the carbon sink effect of Alpine forests in Switzerland might be limited, because generally,
Alpine forests have low growth and yield and (2) a large increase in harvesting may lead to regional carbon sources and necessitate
regional monitoring of increment to avoid overexploitation. As MASSIMO does not include the impacts of climate change, the
conclusions of this study cannot be interpreted as actual predictions into the future but portray the impact of the applied
management actions on the respective trends in carbon stocks and stock changes. They are, therefore, a contribution to support
future management decisions. Further studies should focus on interactions with additional forest functions such as the preservation
of biodiversity, increase the consideration of forest damage and account for the effect of climate change. 相似文献
20.
Mario Tonosaki 《Journal of Wood Science》2009,55(6):390-394
An increase in the amount of harvested wood products (HWP) from sustainable forestry would help to reduce levels of atmospheric
carbon. In the first commitment period of the Kyoto Protocol (2008–2012), this carbon stock effect of HWP is ignored, and
forest harvesting is treated as an instantaneous emission of carbon dioxide. However, in the next commitment period of the
United Nations Framework Convention on Climate Change from 2013, the carbon stock changes resulting from HWP will be taken
into account in the national greenhouse gas inventories. The Japan Wood Research Society called for a roundtable conference
of eight research societies, industrial associations, and nongovernmental organizations that are involved with wood utilization.
At the conference, accounting approaches for HWP were discussed and a consensus was reached that the stock change approach
should be adopted in the next commitment period. 相似文献