Growing Season Length and Soil Moisture Interactively Constrain High Elevation Aboveground Net Primary Production

Ecosystems ◽  
2011 ◽  
Vol 14 (6) ◽  
pp. 963-974 ◽  
Author(s):  
Aaron B. Berdanier ◽  
Julia A. Klein
Ecology ◽  
2020 ◽  
Vol 101 (9) ◽  
Author(s):  
Clifton P. Bueno de Mesquita ◽  
Samuel A. Sartwell ◽  
Steven K. Schmidt ◽  
Katharine N. Suding

2015 ◽  
Vol 29 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Alina Danielewska ◽  
Marek Urbaniak ◽  
Janusz Olejnik

Abstract The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m-2 y-1 per day of growing season, R2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R2 = 0.47, p = 0.058). The CO2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.


2020 ◽  
Author(s):  
Jake D. Graham

Northern peatlands are a major terrestrial carbon (C) store, with an annual sink of 0.1 Pg C yr-1 and a total storage estimate of 547 Pg C. Northern peatlands are also major contributors of atmospheric methane, a potent greenhouse gas. The microtopography of peatlands helps modulate peatland carbon fluxes; however, there is a lack of quantitative characterizations of microtopography in the literature. The lack of formalized schemes to characterize microtopography makes comparisons between studies difficult. Further, many land surface models do not accurately simulate peatland C emissions, in part because they do not adequately represent peatland microtopography and hydrology. The C balance of peatlands is determined by differences in C influxes and effluxes, with the largest being net primary production and heterotrophic respiration, respectively. Tree net primary production at a treed bog in northern Minnesota represented about 13% of C inputs to the peatland, and marks tree aboveground net primary production (ANPP) as an important pathway for C to enter peatlands. Tree species Picea mariana (Black spruce) and Larix Laricina (Tamarack) are typically found in wooded peatlands in North America, and are widely distributed in the North American boreal zone. Therefore, understanding how these species will respond to environmental change is needed to make predictions of peatland C budgets in the future. As the climate warms, peatlands are expected to increase C release to the atmosphere, resulting in a positive feedback loop. Further, climate warming is expected to occur faster in northern latitudes compared to the rest of the globe. The Spruce and Peatland Responses Under Changing Environments (SPRUCE; https://mnspruce.ornl.gov/) manipulates temperature and CO2 concentrations to evaluate the in-situ response of a peatland to environmental change and is located in Minnesota, USA. In this dissertation, I documented surface roughness metrics for peatland microtopography in SPRUCE plots and developed three explicit methods for classifying frequently used microtopographic classes (microforms) for different scientific applications. Subsequently I used one of these characterizations to perform a sensitivity analysis and improve the parameterization of microtopography in a land surface model that was calibrated at the SPRUCE site. The modeled outputs of C from the analyses ranged from 0.8-34.8% when microtopographical parameters were allowed to vary within observed ranges. Further, C related outputs when using our data-driven parameterization differed from outputs when using the default parameterization by -7.9 - 12.2%. Finally, I utilized TLS point clouds to assess the effect elevated temperature and CO2 concentrations had on P. mariana and L. laricina after the first four years of SPRUCE treatments. I observed that P. mariana growth (aboveground net primary production) had a negative response to temperature initially, but the relationship became less pronounced through time. Conversely, L. laricina had no growth response to temperature initially, but developed a positive relationship through time. The divergent growth responses of P. mariana and L. laricina resulted in no detectable change in aboveground net primary production at the community level. Results from this dissertation help improve how peatland microtopography is represented, and improves understanding of how peatland tree growth will respond to environmental change in the future.


2014 ◽  
Vol 20 (11) ◽  
pp. 3457-3470 ◽  
Author(s):  
Irene Garonna ◽  
Rogier de Jong ◽  
Allard J.W. de Wit ◽  
Caspar A. Mücher ◽  
Bernhard Schmid ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document