To constrain global warming, we must strongly curtail greenhouse gas emissions and capture excess atmospheric carbon dioxide
. Regrowing natural forests is a prominent strategy for capturing ...additional carbon
, but accurate assessments of its potential are limited by uncertainty and variability in carbon accumulation rates
. To assess why and where rates differ, here we compile 13,112 georeferenced measurements of carbon accumulation. Climatic factors explain variation in rates better than land-use history, so we combine the field measurements with 66 environmental covariate layers to create a global, one-kilometre-resolution map of potential aboveground carbon accumulation rates for the first 30 years of natural forest regrowth. This map shows over 100-fold variation in rates across the globe, and indicates that default rates from the Intergovernmental Panel on Climate Change (IPCC)
may underestimate aboveground carbon accumulation rates by 32 per cent on average and do not capture eight-fold variation within ecozones. Conversely, we conclude that maximum climate mitigation potential from natural forest regrowth is 11 per cent lower than previously reported
owing to the use of overly high rates for the location of potential new forest. Although our data compilation includes more studies and sites than previous efforts, our results depend on data availability, which is concentrated in ten countries, and data quality, which varies across studies. However, the plots cover most of the environmental conditions across the areas for which we predicted carbon accumulation rates (except for northern Africa and northeast Asia). We therefore provide a robust and globally consistent tool for assessing natural forest regrowth as a climate mitigation strategy.
Citizen science has advanced science for hundreds of years, contributed to many peer-reviewed articles, and informed land management decisions and policies across the United States. Over the last ...10years, citizen science has grown immensely in the United States and many other countries. Here, we show how citizen science is a powerful tool for tackling many of the challenges faced in the field of conservation biology. We describe the two interwoven paths by which citizen science can improve conservation efforts, natural resource management, and environmental protection. The first path includes building scientific knowledge, while the other path involves informing policy and encouraging public action. We explore how citizen science is currently used and describe the investments needed to create a citizen science program. We find that:1.Citizen science already contributes substantially to many domains of science, including conservation, natural resource, and environmental science. Citizen science informs natural resource management, environmental protection, and policymaking and fosters public input and engagement.2.Many types of projects can benefit from citizen science, but one must be careful to match the needs for science and public involvement with the right type of citizen science project and the right method of public participation.3.Citizen science is a rigorous process of scientific discovery, indistinguishable from conventional science apart from the participation of volunteers. When properly designed, carried out, and evaluated, citizen science can provide sound science, efficiently generate high-quality data, and help solve problems.
•Citizen science can improve conservation efforts by building scientific knowledge.•It can also improve conservation efforts by encouraging public action.•Project design must match the needs for science and public involvement.•Citizen science is a powerful tool for tackling conservation challenges.
Shrub willow biomass crops (SWBC) have been developed and promoted for widespread deployment in northeastern and mid-western US as well as in Europe. There are concerns that the production system ...could reduce the soil organic carbon (SOC) over time due to soil disturbances and repeated three-year harvest cycles. This study assesses changes in SOC beneath shrub willow (Salix x dasyclados SV1) biomass crops utilizing a 0, 5, 12, 14, and 19-year old SWBC fields. The sites' management history was similar, suggesting uniform SOC contents prior to plantation establishment. SOC contents were analyzed by total (i.e. 45 cm) and by layer (i.e. 0–15 cm, 16–30 cm, and 31–45 cm) across different ages. Mean SOC contents to 45 cm depth ranged from 175 to 188 Mg ha−1, and showed no statistically significantly differences across ages (p = 0.15) and no interaction between age and depth (p = 0.19). SOC contents differed significantly with soil depth when averaged across ages (p < 0.0001). Statistical analysis of SOC contents by layer, however, showed that SOC contents in the upper 15 cm depth were significantly different (p < 0.001). Linear contrasts of mean SOC contents for the 0–15 cm depth revealed that the 0-year old was significantly different compared with the 5, 12, 14, and 19-year old SWBC.
•Shrub willow biomass crop (SWBC) production system could impact soil organic carbon over time.•We assessed SOC changes in five SWBC chronosequence: 0, 5, 12, 14, and 19-yr old.•Mean SOC contents to 45 cm depth showed no significant changes across the five different ages.•SOC changes occurred in the upper 15 cm depth during the first five years after establishment.•SWBC production system did not result to negative impact on this component of soil resources.
Shrub willow biomass crops (SWBC) have been developed as a biomass feedstock for bioenergy, biofuels, and bioproducts in the northeastern and midwestern USA as well as in Europe. A previous life ...cycle analysis in North America showed that the SWBC production system is a low-carbon fuel source. However, this analysis is potentially inaccurate due to the limited belowground biomass data and the lack of aboveground stool biomass data. This study provides new information on the above- and belowground biomass, the carbon–nitrogen (C/N) ratio, and the root/shoot (R/S) ratio of willow biomass crops (
Salix
×
dasyclados
SV1), which have been in production from 5 to 19 years. The measured amounts of biomass were: 2.6 to 4.1 odt ha
−1
for foliage, 4.9 to 10.9 odt ha
−1
for aboveground stool (AGS), 2.9 to 5.7 odt ha
−1
for coarse roots (CR), 3.1 to 10.2 odt ha
−1
for belowground stool (BGS), and 5.6 to 9.9 odt ha
−1
for standing fine root (FR). The stem biomass production ranged from 7.0 to 18.0 odt ha
−1
year
−1
for the 5- and 19-year-old willows, respectively. C/N ratios ranged from 23 for foliage to 209 for belowground stool. An average R/S ratio of 2.0, calculated as total belowground biomass (BGS, CR, and FR) plus AGS divided by annual stem biomass, can be applied to estimate the total belowground biomass production of a mature SWBC. Based on AGS, BGS, and CR and standing FR biomass data, SWBC showed a net GHG potential of −42.9 Mg CO
2
eq ha
−1
at the end of seven 3-year rotations.
Estimates of aboveground biomass and nutrient stocks are commonly derived using equations that describe tree dimensional relationships. Despite the widespread use of this approach, there is little ...information about whether equations specific to stand age are necessary for accurate biomass predictions. We developed equations for small trees (2–12 cm diameter) of six species in four young northern hardwood stands. We then compared our equations with equations used frequently in the literature that were developed in mature stands (Whittaker et al. 1974. Ecol. Monogr. 44: 233–252). Our equations for yellow birch (Betula alleghaniensis Britt.) predicted 11%–120% greater stem wood for individual trees compared with the equations from Whittaker et al. and, on average, 50% greater aboveground yellow birch biomass in the four stands that we studied. Differences were less pronounced for sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.); our equations predicted, on average, 9% greater aboveground stand biomass for sugar maple and 3% lower biomass for American beech compared with Whittaker et al. Our results suggest that stand age may be an important factor influencing the aboveground allometry and biomass of small yellow birch trees in these developing northern hardwood stands.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Clearcut forest harvesting typically results in large changes in stream water chemistry in northeastern North America. The effects of partial forest harvests on stream chemistry have not received as ...much attention, even though partial cutting is a more common forestry practice than clearcutting in this region. Changes in stream water chemistry following a partial cut are reported here from a 10
ha study catchment in a northern hardwood forest in the Catskill Mountains of southern New York, and are compared to those of a nearby 48
ha reference catchment. The lower two thirds of the treatment catchment was harvested in February–April 2002 by a shelterwood method, such that 33% of the basal area of the catchment was removed. Stream NO
3
−, NH
4
+, Ca
2+, K
+, and total dissolved aluminum (Al
to) concentrations increased significantly after the harvest. Stream Ca
2+, Mg
2+ and NH
4
+ concentrations peaked 5 months after the initiation of the harvest, NO
3
− and K
+ concentrations peaked 6 months after cutting, and Al
to concentrations peaked 1 year after cutting. Streamflow was not significantly affected by the harvest when compared to the flow of three nearby streams. Export of NO
3
− in stream water increased five-fold the year after the cut, and briefly exceeded atmospheric inputs of inorganic nitrogen during 4 months in the fall of 2002. Changes in stream NO
3
− and K
+ concentrations were less than predicted by the relative basal area removed compared with those of a recent nearby clearcut. In contrast, changes in Ca
2+, Mg
2+ and Al
to concentrations were approximately proportional to basal area removal in these two cuts. Stream chemistry returned to values close to those of the pre-cut period and to reference values by early spring of 2003, just over a year after the initiation of the harvest, except for NO
3
− concentrations, which remained elevated above background 18–20 months after completion of the cut.
Over the last century, natural resource management on forest lands has shifted from a singular focus on resource extraction to many foci, such as recreation, tourism, conservation, view-scapes, ...cultural and spiritual values, sustainability, and other values. As a result, the information needs of land managers must now include social and cultural values. In addition, the public's interest in having greater participation in land management decisions and in generating scientific knowledge has never been greater. The generation of scientific knowledge which is expressed primarily through conventional means – such as peer-reviewed publications targeting academics and technology transfer (e.g., patents, licenses, agreements) primarily for government and industry – does not always satisfy the needs of resource managers and public. In recent decades, there has been rapid growth of methods to help bridge this gap by better connecting new knowledge and knowledge generation with public needs. The U.S. Forest Service is making science delivery as important goal as science creation, including structural institutional changes at the interface among researchers, resource managers, and the public, allocating an appropriate portion of project funding specifically for delivery. The Forest Service is considering increasing its use of citizen science and participatory research – which brings resource managers, decision makers, and the public into the research process to varying extents – as part of the agency's science delivery efforts. Here we explore citizen science and participatory research as possible vehicles to augment existing science delivery efforts from the perspective of a federal land management agency. We found that these mechanisms facilitate public involvement in fundamentally different ways. Depending on the type of research and desired use of research outcomes, either citizen science or participatory research could enhance the use of science in some natural resource management discussions, possibly leading to supportable solutions.
Measurements of tree tissue chemistry are influenced by the precision and accuracy of laboratory analyses, sampling position within the tree, variation among replicate trees of the same species, and ...variation from year to year. We characterized these sources of uncertainty for six northern hardwood species and compared them with observed rates of long-term change. Uncertainty associated with laboratory quality control was small (1%–5%) and differed among elements, with K concentrations exhibiting the lowest accuracy and precision. Sampling position within the tree was more important for branches (the coefficient of variation was 23%) and wood (37%) than for foliage or bark (12% for both) (p < 0.001). Foliar N and P concentrations in leaves were less variable than other elements or tissue types both from tree to tree (p = 0.02) and from year to year (p = 0.03), which means that more samples would be needed to detect differences over space or time for Ca, Mg, or K in branches or wood. Concentrations of foliar N increased over 25 years at the Huntington Forest (p ≤ 0.03) by > 16%. Uncertainty analysis can be used to guide the allocation of sampling effort, depending on the elements and tissue types of interest and the objectives of the study.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Forest harvesting disrupts the nitrogen cycle, which may affect stream water quality by increasing nitrate concentrations, reducing pH and acid neutralizing capacity, and mobilizing aluminum and base ...cations. We tested the application of wood chips derived from logging slash to increase immobilization of N after harvesting, which should reduce nitrate flux to streams. In August 2004, a stand of northern hardwoods was patch-clearcut in the Catskill Mountains, NY, and four replicates of three treatments were implemented in five 0.2-ha cut patches. Wood chips were applied to the soil surface at a rate equivalent to the amount of slash smaller than eight inches in diameter (1× treatment). A second treatment doubled that rate (2×), and a third treatment received no chips (0×). Additionally, three uncut reference plots were established in nearby forested areas. Ion exchange resin bags and soil KCl-extractions were used to monitor nitrate availability in the upper 5–10
cm of soil approximately every seven weeks, except in winter. Resin bags indicated that the wood chips retained 30% or 42% of the nitrate pulse, while for KCl extracts, the retention rate was 78% or 100% of the difference between 0× and uncut plots. During the fall following harvest, wood-chip treated plots had resin bag soil nitrate concentrations about 25% of those in 0× plots (
p
=
0.0001). In the first growing season after the cut, nitrate concentrations in wood-chip treated plots for KCl extracts were 13% of those in 0× treatments (
p
=
0.03) in May and about half those in 0× treatments (
p
=
0.01) in July for resin bags. During spring snowmelt, however, nitrate concentrations were high and indistinguishable among treatments, including the uncut reference plots for resin bags and below detection limit for KCl extracts. Wood chips incubated in litterbags had an initial C:N of 125:1, which then decreased to 70:1 after one year of field incubation. These changes in C:N values indicate that the wood-chip application can potentially immobilize between 19 and 38
kg
N
ha
−1 in the first year after harvesting, depending on the rate of wood-chip application. Our results suggest that the application of wood chips following harvesting operations can contribute to the protection of water quality and warrant additional research as a new Best Management Practice following cutting in regions that receive elevated levels of atmospheric N deposition.
Riparian buffers can be effective at removing phosphorus (P) in overland flow, but their influence on subsurface P loading is not well known. Phosphorus concentrations in the soil, soil solution, and ...shallow ground water of 16 paired cropland-buffer plots were characterized during 2004 and 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loams (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that P availability (sodium acetate extractable-P) and soil-landscape variability would affect P release to the soil solution and shallow ground water. Results showed that P availability tended to be greater in crop fields relative to paired buffer plots. Soil P was a good indicator of soil solution dissolved (<0.45 μm) molybdate-reactive P (DRP) concentrations among plots, but was not independently effective at predicting ground water DRP concentrations. Mean ground water DRP in corn fields ranged from < or = 20 to 80 μg L-1, with lower concentrations in hay and buffer plots. More imperfectly drained crop fields and buffers tended to have greater average DRP, particulate (> or =0.45 μm) reactive P (PRP), and dissolved unreactive P (DUP) concentrations in ground water. Soil organic matter and 50-cm depth soil solution DRP in buffers jointly explained 75% of the average buffer ground water DRP variability. Results suggest that buffers were relatively effective at reducing soil solution and shallow ground water DRP concentrations, but their impact on particulate and organic P in ground water was less clear.
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