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Forests, Volume 3, Issue 2 (June 2012) – 17 articles , Pages 155-444

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696 KiB  
Article
Ten Year Evaluation of Carbon Stock in Mangrove Plantation Reforested from an Abandoned Shrimp Pond
by Naohiro Matsui, Keiyo Morimune, Wijarn Meepol and Jirasak Chukwamdee
Forests 2012, 3(2), 431-444; https://doi.org/10.3390/f3020431 - 20 Jun 2012
Cited by 38 | Viewed by 8599
Abstract
Forest carbon stocks—both in terms of the standing biomass and the soil organic carbon (OC)—were monitored in the mangrove plantation reforested from an abandoned shrimp pond for the 10 years following land excavation. Excavation to a level of 25 cm below the existing [...] Read more.
Forest carbon stocks—both in terms of the standing biomass and the soil organic carbon (OC)—were monitored in the mangrove plantation reforested from an abandoned shrimp pond for the 10 years following land excavation. Excavation to a level of 25 cm below the existing ground level increased the inundation time of tidal water from 463 to 7,597 hours per year, resulting in a significant increase of survival/growth rates for planted mangrove species, Rhizophora mucronata (RM) and Bruguiera cylindrica (BC), and of carbon stocks as well. RM showed high rates of standing biomass accumulation with 98.7 ton/ha while 28.8 ton/ha for BC was measured over 10 years in the excavated area. In contrast, the unexcavated area showed low rates of biomass accumulation, 1.04 ton/ha for RM and 0.53 ton/ha for BC in the same period. The excavated area recorded a twofold increase of soil OC in the upper 5 cm of the surface soil from 71.8 to 154.8 ton/ha in 10 years, however it decreased to 68.3 ton/ha in the unexcavated area where soil OC is susceptible to decomposition. These results imply that the potential of carbon sinks in reforested land from abandoned areas cannot be developed unless hydraulic conditions are properly recovered. The fast growing species Avicennia marina (AM) grew quickly for the first two years after colonization but its growth slowed down afterwards, showing a limited ability of carbon capture. Full article
(This article belongs to the Special Issue The Role of Forests for Carbon Capture and Storage)
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Article
Sequestering Carbon in China’s Forest Ecosystems: Potential and Challenges
by Ping Liu and Runsheng Yin
Forests 2012, 3(2), 417-430; https://doi.org/10.3390/f3020417 - 20 Jun 2012
Cited by 20 | Viewed by 6921
Abstract
As part of its efforts to curb greenhouse gas emissions, China has committed to expanding the country’s forest area by 40 million hectares and stocking volume by 1.3 billion m3 from 2006 to 2020. Our analysis suggests that it is very likely [...] Read more.
As part of its efforts to curb greenhouse gas emissions, China has committed to expanding the country’s forest area by 40 million hectares and stocking volume by 1.3 billion m3 from 2006 to 2020. Our analysis suggests that it is very likely that China will realize its goal of forest area expansion; but the target of volume increase represents only a modest gain, which may absorb about 2% of its cumulative carbon emissions. However, China’s forests can be a much more significant carbon sequester and ecosystem services provider if its forest growth rate and stocking level are boosted by improving forest quality and productivity. To that end, however, the silvicultural practices and governance structure must be transformed. Full article
(This article belongs to the Special Issue The Role of Forests for Carbon Capture and Storage)
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Article
The Long-Term Effects of Wildfire and Post-Fire Vegetation on Sierra Nevada Forest Soils
by Dale W. Johnson, Roger F. Walker, Michelle McNulty, Benjamin M. Rau and Watkins W. Miller
Forests 2012, 3(2), 398-416; https://doi.org/10.3390/f3020398 - 20 Jun 2012
Cited by 13 | Viewed by 7936 | Correction
Abstract
This paper compares carbon (C) and nutrient contents in soils (Alfisols derived from andesite), forest floor and vegetation in a former fire (1960) and an adjacent forest in the Sagehen Watershed in the Sierra Nevada Mountains of California. Soils from the former fire [...] Read more.
This paper compares carbon (C) and nutrient contents in soils (Alfisols derived from andesite), forest floor and vegetation in a former fire (1960) and an adjacent forest in the Sagehen Watershed in the Sierra Nevada Mountains of California. Soils from the former fire (now occupied predominantly by Ceanothus velutinus, a nitrogen-fixing shrub) had significantly lower contents of extractable SO42 and P (both Bray and bicarbonate) but significantly greater contents of exchangeable Ca2+ than the adjacent forested site (dominated by Pinus jeffreyii). 15N data suggested that N fixation had occurred in the former fire site, but N contents did not differ between the two sites. O horizon C and nutrient contents did not differ between the two sites, but vegetation C and nutrient contents were significantly greater in the forested than former fire site. These results contrast with those from a nearby, previous study at Little Valley Nevada, also dominated by P. jeffreyii growing on a different soil type (Entisols derived from granite). In the Little Valley study, soil C, N, Ca2+, Mg2+, and K+ contents within the former fire (1981, now also occupied predominantly by Ceanothus velutinus) were greater than in the adjacent forest (Pinus jeffreyii) but soil extractable P contents either did not differ or were greater in the former fire. We conclude that soil parent material is an indirect but strong mediator of the effects of post-fire vegetation on soils in this region, especially with respect to soil P changes, which vary substantially between andesite- and granite-derived soils. Full article
(This article belongs to the Special Issue Long-Term Effects of Fire on Forest Soils)
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Review
Harvesting Carbon from Eastern US Forests: Opportunities and Impacts of an Expanding Bioenergy Industry
by Sarah C. Davis, Michael Dietze, Evan DeLucia, Chris Field, Steven P. Hamburg, Scott Loarie, William Parton, Matthew Potts, Benjamin Ramage, Dan Wang, Heather Youngs and Stephen P. Long
Forests 2012, 3(2), 370-397; https://doi.org/10.3390/f3020370 - 19 Jun 2012
Cited by 23 | Viewed by 11223
Abstract
Eastern forests of the US are valued both as a carbon sink and a wood resource. The amount of biomass that can be harvested sustainably from this biome for bioenergy without compromising the carbon sink is uncertain. Using past literature and previously validated [...] Read more.
Eastern forests of the US are valued both as a carbon sink and a wood resource. The amount of biomass that can be harvested sustainably from this biome for bioenergy without compromising the carbon sink is uncertain. Using past literature and previously validated models, we assessed four scenarios of biomass harvest in the eastern US: partial harvests of mixed hardwood forests, pine plantation management, short-rotation woody cropping systems, and forest residue removal. We also estimated the amount and location of abandoned agricultural lands in the eastern US that could be used for biomass production. Greater carbon storage was estimated to result from partial harvests and residue removals than from plantation management and short-rotation cropping. If woody feedstocks were cultivated with a combination of intensive management on abandoned lands and partial harvests of standing forest, we estimate that roughly 176 Tg biomass y−1 (~330,000 GWh or ~16 billion gallons of ethanol) could be produced sustainably from the temperate forest biome of the eastern US. This biomass could offset up to ~63 Tg C y−1 that are emitted from fossil fuels used for heat and power generation while maintaining a terrestrial C sink of ~8 Tg C y−1. Full article
(This article belongs to the Special Issue The Role of Forests for Carbon Capture and Storage)
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Article
Long and Short-Term Effects of Fire on Soil Charcoal of a Conifer Forest in Southwest Oregon
by Melissa R. A. Pingree, Peter S. Homann, Brett Morrissette and Robyn Darbyshire
Forests 2012, 3(2), 353-369; https://doi.org/10.3390/f3020353 - 19 Jun 2012
Cited by 28 | Viewed by 11207
Abstract
In 2002, the Biscuit Wildfire burned a portion of the previously established, replicated conifer unthinned and thinned experimental units of the Siskiyou Long-Term Ecosystem Productivity (LTEP) experiment, southwest Oregon. Charcoal C in pre and post-fire O horizon and mineral soil was quantified by [...] Read more.
In 2002, the Biscuit Wildfire burned a portion of the previously established, replicated conifer unthinned and thinned experimental units of the Siskiyou Long-Term Ecosystem Productivity (LTEP) experiment, southwest Oregon. Charcoal C in pre and post-fire O horizon and mineral soil was quantified by physical separation and a peroxide-acid digestion method. The abrupt, short-term fire event caused O horizon charcoal C to increase by a factor of ten to >200 kg C ha−1. The thinned wildfire treatment produced less charcoal C than unthinned wildfire and thinned prescribed fire treatments. The charcoal formation rate was 1 to 8% of woody fuels consumed, and this percentage was negatively related to woody fuels consumed, resulting in less charcoal formation with greater fire severity. Charcoal C averaged 2000 kg ha−1 in 0–3 cm mineral soil and may have decreased as a result of fire, coincident with convective or erosive loss of mineral soil. Charcoal C in 3–15 cm mineral soil was stable at 5500 kg C ha−1. Long-term soil C sequestration in the Siskiyou LTEP soils is greatly influenced by the contribution of charcoal C, which makes up 20% of mineral soil organic C. This research reiterates the importance of fire to soil C in a southwestern Oregon coniferous forest ecosystem. Full article
(This article belongs to the Special Issue Long-Term Effects of Fire on Forest Soils)
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Review
Carbon Content of Tree Tissues: A Synthesis
by Sean C. Thomas and Adam R. Martin
Forests 2012, 3(2), 332-352; https://doi.org/10.3390/f3020332 - 19 Jun 2012
Cited by 349 | Viewed by 23435
Abstract
Assessing the potential for forest carbon (C) capture and storage requires accurate assessments of C in live tree tissues. In the vast majority of local, regional, and global assessments, C content has been assumed to be 50% of tree biomass; however, recent studies [...] Read more.
Assessing the potential for forest carbon (C) capture and storage requires accurate assessments of C in live tree tissues. In the vast majority of local, regional, and global assessments, C content has been assumed to be 50% of tree biomass; however, recent studies indicate that this assumption is not accurate, with substantial variation in C content among tree species as well as among tissue types. Here we conduct a comprehensive literature review to present a global synthesis of C content in tissues of live trees. We found a total of 253 species-specific stem wood C content records in 31 studies, and an additional 34 records of species with C content values of other tissues in addition to stem wood. In all biomes, wood C content varied widely across species ranging from 41.9–51.6% in tropical species, 45.7–60.7% in subtropical/Mediterranean species, and 43.4–55.6% in temperate/boreal species. Stem wood C content varied significantly as a function of biome and species type (conifer, angiosperm). Conifer species exhibited greater wood C content than angiosperm species (50.8 ± 0.7% (95% C.I.) and 47.7 ± 0.3%, respectively), a trend that was consistent among all biomes. Although studies have documented differences in C content among plant tissues, interspecific differences in stem wood appear to be of greater importance overall: among species, stem wood C content explained 37, 76, 48, 81, and 63% respectively of the variation in bark, branch, twig, coarse root, and fine root C content values, respectively. In each case, these intraspecific patterns approximated 1:1 linear relationships. Most published stem wood C content values (and all values for other tree tissues) are based on dried wood samples, and so neglect volatile C constituents that constitute on average 1.3–2.5% of total C in live wood. Capturing this volatile C fraction is an important methodological consideration for future studies. Our review, and associated data compilation, provides empirically supported wood C fractions that can be easily incorporated into forest C accounting, and may correct systematic errors of ~1.6–5.8% in forest C assessments. Full article
(This article belongs to the Special Issue The Role of Forests for Carbon Capture and Storage)
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Article
Impacts of Prescribed Fire Frequency on Coarse Woody Debris Volume, Decomposition and Termite Activity in the Longleaf Pine Flatwoods of Florida
by James L. Hanula, Michael D. Ulyshen and Dale D. Wade
Forests 2012, 3(2), 317-331; https://doi.org/10.3390/f3020317 - 06 Jun 2012
Cited by 25 | Viewed by 8293
Abstract
Longleaf pine (Pinus palustris) ecosystems have been reduced dramatically throughout their range. Prescribed burning is considered the best way to restore and maintain plant communities associated with longleaf pine, but little is known about its effects on coarse woody debris and [...] Read more.
Longleaf pine (Pinus palustris) ecosystems have been reduced dramatically throughout their range. Prescribed burning is considered the best way to restore and maintain plant communities associated with longleaf pine, but little is known about its effects on coarse woody debris and associated organisms. We conducted a 5-year study on the Osceola National Forest in northeastern Florida to determine how dormant-season prescribed burns at different frequencies (annual, biennial, quadrennial or unburned) applied over a 40-year period affected coarse woody debris volume, decomposition and nitrogen content, and subterranean termite (Reticulitermes spp.) activity. Burn frequency had no effect on standing dead tree or log volumes. However, freshly cut longleaf pine logs placed in the plots for four years lost significantly less mass in annually burned plots than in unburned plots. The annual exponential decay coefficient estimate from all logs was 0.14 yr−1 (SE = 0.01), with the estimated times for 50 and 95% loss being 5 and 21.4 years, respectively. Termite presence was unaffected by frequent burning, suggesting they were able to survive the fires underground or within wood, and that winter burning did not deplete their food resources. Full article
(This article belongs to the Special Issue Long-Term Effects of Fire on Forest Soils)
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Article
Using Silviculture to Influence Carbon Sequestration in Southern Appalachian Spruce-Fir Forests
by Patrick T. Moore, R. Justin DeRose, James N. Long and Helga Van Miegroet
Forests 2012, 3(2), 300-316; https://doi.org/10.3390/f3020300 - 04 Jun 2012
Cited by 17 | Viewed by 8423
Abstract
Enhancement of forest growth through silvicultural modification of stand density is one strategy for increasing carbon (C) sequestration. Using the Fire and Fuels Extension of the Forest Vegetation Simulator, the effects of even-aged, uneven-aged and no-action management scenarios on C sequestration in a [...] Read more.
Enhancement of forest growth through silvicultural modification of stand density is one strategy for increasing carbon (C) sequestration. Using the Fire and Fuels Extension of the Forest Vegetation Simulator, the effects of even-aged, uneven-aged and no-action management scenarios on C sequestration in a southern Appalachian red spruce-Fraser fir forest were modeled. We explicitly considered C stored in standing forest stocks and the fate of forest products derived from harvesting. Over a 100-year simulation period the even-aged scenario (250 Mg C ha1) outperformed the no-action scenario (241 Mg C ha1) in total carbon (TC) sequestered. The uneven-aged scenario approached 220 Mg C ha1, but did not outperform the no-action scenario within the simulation period. While the average annual change in C (AAC) of the no-action scenario approached zero, or carbon neutral, during the simulation, both the even-aged and uneven-aged scenarios surpassed the no-action by year 30 and maintained positive AAC throughout the 100-year simulation. This study demonstrates that silvicultural treatment of forest stands can increase potential C storage, but that careful consideration of: (1) accounting method (i.e., TC versus AAC); (2) fate of harvested products and; (3) length of the planning horizon (e.g., 100 years) will strongly influence the evaluation of C sequestration. Full article
(This article belongs to the Special Issue The Role of Forests for Carbon Capture and Storage)
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Article
Site Productivity and Forest Carbon Stocks in the United States: Analysis and Implications for Forest Offset Project Planning
by Coeli M. Hoover and James E. Smith
Forests 2012, 3(2), 283-299; https://doi.org/10.3390/f3020283 - 04 Jun 2012
Cited by 6 | Viewed by 6781
Abstract
The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a [...] Read more.
The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a broad analysis of forest inventory data using site quality indicators to provide guidance to managers planning land acquisition for forest-based greenhouse gas mitigation projects. Specifically, we summarize two condition class indicators of site productivity within the FIA forest inventory database—physclcd and siteclcd—as they relate to current aboveground live tree carbon stocks. Average carbon density is higher on more productive sites, but compared to the overall variability among sites, the differences are relatively small for all but the highest and lowest site classes. Some minor differences in eastern- versus western-forests were apparent in terms of how carbon on the least productive sites differed from most other forest land over time. Overall results suggest that xeric sites in most regions as well as sites that correspond to the lowest, non-productive classifications of forest land should preferentially not be used forestry-based greenhouse gas mitigation projects, but all other forest areas appear to be suitable. Full article
(This article belongs to the Special Issue The Role of Forests for Carbon Capture and Storage)
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Article
Geospatial Analysis Application to Forecast Wildfire Occurrences in South Carolina
by Joel A. Feltman, Thomas J. Straka, Christopher J. Post and Stephen L. Sperry
Forests 2012, 3(2), 265-282; https://doi.org/10.3390/f3020265 - 25 May 2012
Cited by 13 | Viewed by 8753
Abstract
Wildfire occurrence and intensity have increased over the last few decades and, at times, have been national news. Wildfire occurrence is somewhat predictable based on physical factors like meteorological conditions, fuel loads, and vegetation dynamics. Socioeconomic factors have been not been widely used [...] Read more.
Wildfire occurrence and intensity have increased over the last few decades and, at times, have been national news. Wildfire occurrence is somewhat predictable based on physical factors like meteorological conditions, fuel loads, and vegetation dynamics. Socioeconomic factors have been not been widely used in wildfire occurrence models. We used a geospatial (or geographical information system) analysis approach to identify socioeconomic variables that contribute to wildfire occurrence. Key variables considered were population change, population density, poverty rate, educational level, geographic mobility, and road density (transportation network). Hot spot analysis was the primary research tool. Wildfire occurrence seemed to be positively related to low population densities, low levels of population change, high poverty rate, low educational attainment level, and low road density. Obviously, some of these variables are correlated and this is a complex problem. However, socioeconomic variables appeared to contribute to wildfire occurrence and should be considered in development of wildfire occurrence forecasting models. Full article
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699 KiB  
Article
Challenges of Opportunity Cost Analysis in Planning REDD+: A Honduran Case Study of Social and Cultural Values Associated with Indigenous Forest Uses
by Spencer T. Plumb, Erik A. Nielsen and Yeon-Su Kim
Forests 2012, 3(2), 244-264; https://doi.org/10.3390/f3020244 - 24 May 2012
Cited by 22 | Viewed by 9013
Abstract
The REDD Programme is predicated on the assumption that developed countries will provide sufficient funds to offset opportunity costs associated with avoiding deforestation. The role of non-market values in indigenous land management may challenge the efficacy of compensation schemes targeted at meeting opportunity [...] Read more.
The REDD Programme is predicated on the assumption that developed countries will provide sufficient funds to offset opportunity costs associated with avoiding deforestation. The role of non-market values in indigenous land management may challenge the efficacy of compensation schemes targeted at meeting opportunity costs as calculated in traditional opportunity cost analysis (OCA). Furthermore it is unclear how these economic incentives might affect social and cultural values linked to land-use norms, livelihoods, and local governance. This study explores the economic, social and cultural values of forest uses for a Miskito community in the Rio Plátano Biosphere Reserve in Honduras. Data were collected using household surveys, farm visits, and community workshops. OCA indicates potential for successful REDD+ payment schemes; however it is an inadequate method to account for subsistence and cultural opportunity costs associated with avoided deforestation. Compensation to change land-use practices may undermine governance institutions necessary to address deforestation in the region. Our results indicate that small-scale agriculture and other forest-based subsistence activities are important cultural practices for maintaining Miskito identity and forest management institutions. Recommendations are offered for using OCA to develop REDD+ projects that recognize the linkages between social and cultural values and forest management by focusing on approaches that consider a full range of economic, social and cultural opportunity costs. Full article
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Article
Effects of Low Levels of Dispersed Retention on the Growth and Survival of Young, Planted Douglas-Fir
by Nicholas J. Smith and William J. Beese
Forests 2012, 3(2), 230-243; https://doi.org/10.3390/f3020230 - 16 May 2012
Cited by 5 | Viewed by 7508
Abstract
Three large-scale, experimental, dispersed residual tree sites established in coastal British Columbia, Canada were measured for planted Douglas-fir tree growth and survival five to six years after planting. The dispersed trees were predominantly large diameter (60 cm+) Douglas-fir left with a range of [...] Read more.
Three large-scale, experimental, dispersed residual tree sites established in coastal British Columbia, Canada were measured for planted Douglas-fir tree growth and survival five to six years after planting. The dispersed trees were predominantly large diameter (60 cm+) Douglas-fir left with a range of 0% to 30% of the original forest stand basal area (0 m2 ha−1 to 14 m2 ha−1). Two sites had 0%, 5% and 15% retention, while one site had 0%, 5%, 10% and 30% retention. The trees were measured in sector plots established to randomly sample the range of microsites in each treatment. There was no detectable difference between height and basal diameter growth or mortality rates between the retention treatments over the measurement period, except for a reduction of basal diameter growth at the 30% retention level (p < 0.05). Thus a statistically significant impact on growth was demonstrated for the 30% retention compared to the 0% retention level. We expected intermediate growth rates between the 0% and the other lower retention levels but were unable to demonstrate this due to the low statistical power of the test (10 observations) and high site variability for these very young trees. Full article
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Article
Do Anthropogenic Dark Earths Occur in the Interior of Borneo? Some Initial Observations from East Kalimantan
by Douglas Sheil, Imam Basuki, Laura German, Thomas W. Kuyper, Godwin Limberg, Rajindra K. Puri, Bernard Sellato, Meine Van Noordwijk and Eva Wollenberg
Forests 2012, 3(2), 207-229; https://doi.org/10.3390/f3020207 - 07 May 2012
Cited by 21 | Viewed by 12931
Abstract
Anthropogenic soils of the Amazon Basin (Terra Preta, Terra Mulata) reveal that pre-Colombian peoples made lasting improvements in the agricultural potential of nutrient-poor soils. Some have argued that applying similar techniques could improve agriculture over much of the humid tropics, [...] Read more.
Anthropogenic soils of the Amazon Basin (Terra Preta, Terra Mulata) reveal that pre-Colombian peoples made lasting improvements in the agricultural potential of nutrient-poor soils. Some have argued that applying similar techniques could improve agriculture over much of the humid tropics, enhancing local livelihoods and food security, while also sequestering large quantities of carbon to mitigate climate change. Here, we present preliminary evidence for Anthropogenic Dark Earths (ADEs) in tropical Asia. Our surveys in East Kalimantan (Indonesian Borneo) identified several sites where soils possess an anthropogenic development and context similar in several respects to the Amazon’s ADEs. Similarities include riverside locations, presence of useful fruit trees, spatial extent as well as soil characteristics such as dark color, high carbon content (in some cases), high phosphorus levels, and improved apparent fertility in comparison to neighboring soils. Local people value these soils for cultivation but are unaware of their origins. We discuss these soils in the context of local history and land-use and identify numerous unknowns. Incomplete biomass burning appears key to these modified soils. More study is required to clarify soil transformations in Borneo and to determine under what circumstances such soil improvements might remain ongoing. Full article
(This article belongs to the Special Issue Long-Term Effects of Fire on Forest Soils)
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Article
A Comparison of Invasive Acer platanoides and Native A. saccharum First-Year Seedlings: Growth, Biomass Distribution and the Influence of Ecological Factors in a Forest Understory
by Marie Lapointe and Jacques Brisson
Forests 2012, 3(2), 190-206; https://doi.org/10.3390/f3020190 - 03 May 2012
Cited by 7 | Viewed by 7951
Abstract
Invasive shade tolerant species can have profound and long-lasting detrimental effects even on previously undisturbed forests. In North American forests, the invasive Acer platanoides is capable of dominating the understory where it could displace the native Acer saccharum. To understand the relative [...] Read more.
Invasive shade tolerant species can have profound and long-lasting detrimental effects even on previously undisturbed forests. In North American forests, the invasive Acer platanoides is capable of dominating the understory where it could displace the native Acer saccharum. To understand the relative importance of various ecological factors in a forest understory on their establishment, we transplanted A. platanoides and A. saccharum seedlings in an urban sugar maple forest understory and their growth and survival were compared over a growing season. Seedlings did not differ in height, but biomass growth and assimilation rates were twice as high for the invasive species. Ecological variables accounted for only 23–24% of variation in growth. Seedlings of A. platanoides appeared to capture light more efficiently, with over 150% greater foliage biomass and surface area. A. saccharum seedlings were more negatively affected by herbivory. The more robust A. platanoides seedlings presented characteristics that could allow them to better grow and survive in shaded understories than their native congeners. Full article
(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)
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Article
Improving Woody Biomass Estimation Efficiency Using Double Sampling
by David L. Parrott, John M. Lhotka, Songlin Fei and B. Scott Shouse
Forests 2012, 3(2), 179-189; https://doi.org/10.3390/f3020179 - 03 May 2012
Cited by 2 | Viewed by 5612
Abstract
Although double sampling has been shown to be an effective method to estimate timber volume in forest inventories, only a limited body of research has tested the effectiveness of double sampling on forest biomass estimation. From forest biomass inventories collected over 9,683 ha [...] Read more.
Although double sampling has been shown to be an effective method to estimate timber volume in forest inventories, only a limited body of research has tested the effectiveness of double sampling on forest biomass estimation. From forest biomass inventories collected over 9,683 ha using systematic point sampling, we examined how a double sampling scheme would have affected precision and efficiency in these biomass inventories. Our results indicated that double sample methods would have yielded biomass estimations with similar precision as systematic point sampling when the small sample was ≥ 20% of the large sample. When the small to large sample time ratio was 3:1, relative efficiency (a combined measure of time and precision) was highest when the small sample was a 30% subsample of the large sample. At a 30% double sample intensity, there was a < 3% deviation from the original percent margin of error and almost half the required time. Results suggest that double sampling can be an efficient tool for natural resource managers to estimate forest biomass. Full article
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Article
Stump and Root Biomass of Poplar Stands
by Tord Johansson and Birger Hjelm
Forests 2012, 3(2), 166-178; https://doi.org/10.3390/f3020166 - 18 Apr 2012
Cited by 26 | Viewed by 8064
Abstract
Today there is an increasing demand for biomass for use in energy production. In this study we investigated stumps and roots from six poplar (Populus sp.) stands growing on former farmland in Sweden, situated between latitudes 55 and 60°N. The mean age [...] Read more.
Today there is an increasing demand for biomass for use in energy production. In this study we investigated stumps and roots from six poplar (Populus sp.) stands growing on former farmland in Sweden, situated between latitudes 55 and 60°N. The mean age of the poplar was 20 years (range 16–23), the mean stand density 1151 stems ha−1 (range 361–3279), and the mean diameter at breast height (over bark) 288 mm (range 81–574). All poplar stands were on clay soils (light and medium clay and light clay tills).The mean dry mass weight of the 72 excavated stumps was 45 ± 39 kg (range 1–185), with the roots ≥ 50 mm weighing 14 ± 16 kg (range 0.2–87). Dry mean stump weight represented 21% (by dry weight) of the stem. The mean total dry weight per hectare for stumps amounted to 34.9 ± 21.8 (range 12.9–66.9) tons and the equivalent value for roots was 12.0 ± 9.6 (range 4.7–10.9) tons. The excavation of below-ground biomass can either focus on the stump or the stump and parts of the root system. Depending on the combination of soil type and soil moisture the weight of soil adhering to stumps and the cleaning requirements will vary. Full article
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Article
Factors Influencing Visitors to Suburban Open Space Areas near a Northern Japanese City
by Tetsuya Aikoh, Reina Abe, Ryo Kohsaka, Mari Iwata and Yasushi Shoji
Forests 2012, 3(2), 155-165; https://doi.org/10.3390/f3020155 - 12 Apr 2012
Cited by 14 | Viewed by 7019
Abstract
Visitor information often serves as the basis for the management plan of parks. However, there exist few scientific and fundamental surveys for parks and open spaces in Japan. We analyzed the correlation between the number of visitors and the various factors in a [...] Read more.
Visitor information often serves as the basis for the management plan of parks. However, there exist few scientific and fundamental surveys for parks and open spaces in Japan. We analyzed the correlation between the number of visitors and the various factors in a suburban open space in a northern Japanese city, Takino Park. To explain the fluctuations in the number of visitors in Takino Park, multiple regression analyses with the stepwise method were conducted. The analyses employed social factors and meteorological factors, such as the day of the week, school vacations, temperature and the weather. The results show that the most influential factor is the day of the week, i.e., Sundays and holidays. The weather is also influential as the number of visitors decreases on rainy and snowy days. Comparing different seasons of the year, we found that influential factors varied from one season to the other. A key distinguishing finding of our results is that the weather conditions at the departure site and the weather forecast are also determining factors. These findings will help park managers understand the current situations and examine future management strategies to maintain and enhance visitor satisfaction, and improve information services. Full article
(This article belongs to the Special Issue Expanding Forests’ Benefits: Forest-based Recreation and Tourism)
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