Tree growth response to climate change at the deciduous–boreal forest ecotone, Ontario, Canada

2005 ◽  
Vol 35 (11) ◽  
pp. 2709-2718 ◽  
Author(s):  
D Goldblum ◽  
L S Rigg

We consider the implications of climate change on the future of the three dominant forest species, sugar maple (Acer saccharum Marsh.), white spruce (Picea glauca (Moench) Voss), and balsam fir (Abies balsamea (L.) Mill.), at the deciduous–boreal forest ecotone, Ontario, Canada. Our analysis is based on individual species responses to past monthly temperature and precipitation conditions in light of modeled (general circulation model) monthly temperature and precipitation conditions in the study area for the 2080s. We then consider the tree species sensitivity to past climate with predicted conditions for the 2080 period. Sugar maple, located at its northern limit in the study area, shows the greatest potential for increased growth rates under the predicted warming and altered precipitation regime. White spruce is likely to benefit less, while the understory dominant balsam fir is likely to experience a decrease in growth potential. These projected changes would enhance the future status of sugar maple at its northern limit and facilitate range expansion northward in response to global warming.

2003 ◽  
Vol 20 (4) ◽  
pp. 167-174
Author(s):  
Nobutaka Nakamura ◽  
Paul M. Woodard ◽  
Lars Bach

Abstract Tree boles in the boreal forests of Alberta, Canada will split once killed by a stand-replacing crown fire. A total of 1,485 fire-killed trees were sampled, 1 yr after burning, in 23 plots in 14 widely separated stands within a 370,000 ha fire. Sampling occurred in the Upper and Lower Foothills natural subregions. The frequency of splitting varied by species but averaged 41% for all species. The order in the frequency of splitting was balsam fir, black spruce, white spruce and lodgepole pine. The type of splitting (straight, spiral, or multiple) varied by species, as did the position of the split on the tree bole. Aspect or solar angle was not statistically related to the type or occurrence of splitting.


Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 27
Author(s):  
Enzai Du ◽  
Yang Tang

Climate change is exerting profound impacts on the structure and function of global boreal forest. Compared with their northern counterparts, trees growing at the southern boreal forest and the temperate-boreal forest ecotone likely show distinct responses to climate change. Based on annual basal areal increment (BAI) of Dahurian larch (Larix gmelinii Rupr.) plantations with similar ages, tree densities and soil nutrient conditions, we investigated the tree growth responses to inter-annual climate variations at an Asian temperate-boreal forest ecotone and nearby boreal sites in northeast China. Annual BAI changed nonlinearly with cambial age in the form of a lognormal curve. The maximum annual BAI showed no significant difference between the two bioregions, while annual BAI peaked at an elder age at the boreal-temperate forest ecotone. After eliminating the age associated trend, conditional regression analyses indicate that residual BAI at the boreal sites increased significantly with higher growing-season mean nighttime minimum temperature and non-growing-season precipitation, but decreased significantly with higher growing-season mean daytime maximum temperature during the past three decades (1985–2015). In contrast, residual BAI at the boreal-temperate forest ecotone only showed a positive and weak response to inter-annual variations of growing-season precipitation. These findings suggest distinct effects of inter-annual climate variation on the growth of boreal trees at the temperate-boreal forest ecotone in comparison to the southern boreal regions, and highlight future efforts to elucidate the key factors that regulate the growth ofthe southernmost boreal trees.


2020 ◽  
Vol 12 (20) ◽  
pp. 8373
Author(s):  
Matilda Cresso ◽  
Nicola Clerici ◽  
Adriana Sanchez ◽  
Fernando Jaramillo

Paramo ecosystems are tropical alpine grasslands, located above 3000 m.a.s.l. in the Andean mountain range. Their unique vegetation and soil characteristics, in combination with low temperature and abundant precipitation, create the most advantageous conditions for regulating and storing surface and groundwater. However, increasing temperatures and changing patterns of precipitation due to greenhouse-gas-emission climate change are threatening these fragile environments. In this study, we used regional observations and downscaled data for precipitation and minimum and maximum temperature during the reference period 1960–1990 and simulations for the future period 2041–2060 to study the present and future extents of paramo ecosystems in the Chingaza National Park (CNP), nearby Colombia’s capital city, Bogotá. The historical data were used for establishing upper and lower precipitation and temperature boundaries to determine the locations where paramo ecosystems currently thrive. Our results found that increasing mean monthly temperatures and changing precipitation will render 39 to 52% of the current paramo extent in CNP unsuitable for these ecosystems during the dry season, and 13 to 34% during the wet season. The greatest loss of paramo area will occur during the dry season and for the representative concentration pathway (RCP) scenario 8.5, when both temperature and precipitation boundaries are more prone to be exceeded. Although our initial estimates show the future impact on paramos and the water security of Bogotá due to climate change, complex internal and external interactions in paramo ecosystems make it essential to study other influencing climatic parameters (e.g., soil, topography, wind, etc.) apart from temperature and precipitation.


2021 ◽  
pp. 121-142
Author(s):  
Sridhara Nayak ◽  
Tetsuya Takemi

AbstractThis study explores a comprehensive assessment of future climate change in terms of the climatologies, distribution patterns, annual cycles, and frequency distributions of temperature and precipitation over India by analyzing 190 mega-ensemble experimental results. The results indicate that the annual mean surface temperatures over Indian regions are typically 25 ℃ or higher in the present climate (1951–2010) and are expected to increase by 3–5 ℃ in the future climate (2051–2110). Some desert regions in the west and tropical humid climate types in the central and south regions of the country show possible temperature increases of 4–5 ℃, while the temperatures over the subtropical humid climates in the north and east regions of the country show increases of 3–4 ℃. The precipitation amounts over the arid and semiarid climate types in the western region and over some tropical rainforest climate zones in the southwest region show increases of 0.5 mm d−1 in the future climate, and the precipitation amounts over the temperate, rainy climate types in the northeast region show increases of more than 1 mm d−1. This study also discusses future changes in various climatic variables, including vertical velocity, air temperature, specific humidity, cloud cover, and relative humidity.


2021 ◽  
Author(s):  
Eshrat Fatima ◽  
Akif Rahim ◽  
Shabeh ul Hasson ◽  
Mujtaba Hassan ◽  
Farhan Aziz ◽  
...  

<p>The hydrological cycle is generally known as a recurring result of various forms of water movement and changes in its physical state in nature over a specific area of ​​the earth (river or Lake Basin, a continent, or the whole earth). It is most likely that the increase in global warming will intensively affect the hydrological cycle regionally and globally which will ultimately affect the ecosystem, public health, and municipal water demand. Therefore, the resiliency of watershed to extreme events play a vital role to understand the health of the watershed. This study aims to quantify the resiliency of the Hunza watershed, which lies in the Western Karakoram, to dry conditions under the climate change projections i.e. RCPs 2.6, 4.5, and 8.5. We used a fully distributed hydrological model SPHY to simulate the impact of climate change on future water availability. The SPHY Model was calibration and validation for the time periods (1994-2000) and (2001-2006) respectively. The performance of the model was tested through statistical analysis such as Nash-Sutcliffe efficiency (NSE), coefficient of determination (R<sup>2</sup>), percentage of bias (PBIAS), and root mean square error (RMSE).To develop future water scenarios, the daily temperature, and precipitation data were obtained from the CORDEX South Asia domain under three Representative Concentration Pathways (RCPs). The empirical quantile mapping method was used for the correction of the daily temperature and precipitation biases under the regional scale. The model was run for near (2007-2036), mid (2037-2066), and far-future (2067-2096) climate projections i.e. RCP2.6, RCP4.5, and RCP8.5. The resilience of watershed defined as the speed of recovery from dry conditions. The monthly Streamflow Drought Index (SDI) was used as an indicator of the dry condition. The resiliency of the watershed determines with the threshold levels of -0.5 and -1.0. The analysis indicates that the resiliency of the watershed has increased from 0.3 to 0.5 in the future under the RCP of 2.6. The value of resilience under the RCP of 4.5 is 0.29, 0.45, and 0.52 for near, mid, and far futures respectively. Under extreme climate conditions RCP 8.5, the watershed resilience is 0.2 in the near future and 0.3 in the mid-future, and 0.6 for the far future. Therefore, it can be concluded that the health of the reservoirs will be very good in the future to stabilize the drought.  </p>


2003 ◽  
Vol 79 (3) ◽  
pp. 462-474 ◽  
Author(s):  
J. Loo ◽  
N. Ives

The Acadian Forest Region comprises the three Maritime Provinces of Canada, each of which has a distinct history resulting in different patterns of land ownership, land use, and impacts on the forest. The region encompasses a high degree of physiographic and biological diversity, being situated where the warm, moist influence of the Gulf Stream from the south collides with the cold Labrador Current and the boreal forest gradually gives way to mostly deciduous forest. Natural forest types in the Acadian Forest Region include rich tolerant hardwood, similar to the deciduous forests to the south; spruce-fir forest, similar to boreal forest to the north; and an array of coniferous, deciduous, and mixed intermediate types. Red spruce (Picea rubens Sarg.), yellow birch (Betula alleghaniensis Britt.), sugar maple (Acer saccharum Marsh.) and balsam fir (Abies balsamea (L.) Mill.) are considered characteristic of the Acadian Forest Region. Except for one quantitative study in one county of New Brunswick, and another study on Prince Edward Island, most knowledge of the historical forest condition has been gleaned from early descriptions by explorers, surveyors, and settlers of the Maritimes region. Although some regions have been affected much more than others, little, if any forested area has escaped human influence over the past four centuries. A general result of human activities has been a shift in successional status and age distribution, with increased frequency of relatively young, often even-aged, early successional forest types including balsam fir, white spruce (Picea glauca (Moench) Voss), red maple (Acer rubrum L.), white birch (Betula papyrifera Marsh.), and trembling aspen (Populus tremuloides Michx.). Both the abundance and age of late-successional species such as sugar maple, red spruce, eastern hemlock (Tsuga canadensis L. Carrière), yellow birch, cedar (Thuja occidentalis L.), and beech (Fagus grandifolia Ehrh.) have declined. Key words: pre-European forest, Maritime Provinces, historical ecology, witness trees, Acadian forest types, natural disturbance


2014 ◽  
Vol 11 (3) ◽  
pp. 3615-3652 ◽  
Author(s):  
Y. Kim

Abstract. Winter and spring soil CO2 efflux-measurements represent a significant component in the assessment of annual carbon budgets of tundra and boreal forest ecosystems, as a response to climate change in the Arctic. This study was conducted to quantify CO2 efflux using a portable chamber system at representative sites along the trans-Alaska pipeline. The sites here are characterized as three tundra, two white spruce, and three black spruce forest sites during winter and spring seasons of 2010 to 2012; study of these sites will offer a better understanding of winter and spring carbon contributions to the annual carbon budget, as well as their affecting parameters by the effect of ablation ring in spring. 3 yr spring CO2 efflux depends on soil temperature at 5 cm depth on a regional scale. At their highest, Q10 values were 4.2 × 106, within the exposed tussock tundra of the upland tundra site, as tundra soils warmed from −0.9 to 0.5 °C, involving the soil microbial activity. With the forest census (400 m2) of the two white spruce forest sites, CO2 emissions were estimated to be 35 to 145 gC day−1 in winter and 56 to 1980 gC day−1 in spring, corresponding to 1–3 and 1–27% of annual carbon, respectively. The contributions from spring CO2 emissions are likely to increase as exposed soils widen in average length (major axis) from east, west, and south, as well as north-side length (minor axis). Considering the periods of winter and spring seasons across tundra and boreal forests, average winter- and spring-seasonal CO2 contributions to annual carbon budgets correspond roughly to 14–22% in tundra and 9–24% in boreal forest sites during 2011–2012. Contributions from spring carbon comparable to growing season CO2 emissions are sensitive to subtle changes at the onset of spring and during the snow-covered period in northern high latitudes, in response to recent Arctic climate change.


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