Early responses of elevated nutrient input on above-ground net primary production of a lower-montane tropical forest in Uganda

2020 ◽  
Author(s):  
Raphael Manu ◽  
Marife D. Corre ◽  
Edzo Veldkamp ◽  
Oliver van Straaten
Keyword(s):  
Primary Production ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Net Primary Production ◽  
Forest Growth ◽  
Nutrient Addition ◽  
Litter Production ◽  
N Addition ◽  
Litter Fall ◽  
Montane Tropical Forest

<p>Nutrient availability in tropical forest ecosystems plays a critical role in sustaining forest growth and productivity. Observational evidence for nutrient limitations on net primary productivity (NPP) in the tropics is rare yet crucial for predicting the impacts of human-induced changes on tropical forests, particularly for underrepresented tropical regions in Africa. In an ecosystem-scale nutrient manipulation experiment, we assessed the response of different components of above-ground net primary production (ANPP) to nutrient addition of nitrogen (N), phosphorus (P), potassium (K) and all possible combinations (NP, NK, PK, and NPK) at rates of 125 kg N ha<sup>-1</sup>yr<sup>-1</sup>, 50 kg P ha<sup>-1</sup> yr<sup>-1</sup> and 50 kg K ha<sup>-1</sup>yr<sup>-1</sup>.</p><p>We established 32 (8 treatments × 4 replicates) experimental plots of 40 × 40 m<sup>2</sup> each and measured stem growth of over 15,000 trees with diameter at breast height (dbh) ≥ 1 cm as well as litter production and above-ground woody biomass production (AWBP), of a lower-montane tropical forest (1100 m a.s.l.) in northwestern Uganda.</p><p>After 18 months of nutrient addition, we found that different aspects of ANPP, including litter production and AWBP are controlled by multiple soil nutrients. Specifically, we measured higher total fine-litter production in the N (13.6 ± 1.4 Mg ha<sup>-1 </sup>yr<sup>-1</sup>) and K (13.3 ± 1.8 Mg ha<sup>-1 </sup>yr<sup>-1</sup>) addition plots than the control (11.1 ± 0.6 Mg ha<sup>-1 </sup>yr<sup>-1</sup>) plots. Both reproductive litter (flowers and fruits; 10% of total fine-litter fall) and leaf litter (62% of total fine-litter fall) significantly increased with K addition. In general, fine-litter production in our plots is higher than what has been reported so far for lower-montane tropical forests. Increased AWBP is associated with N addition plots. The response of trees to nutrient addition however, varied with tree sizes. Trees with dbh between 10 – 30 cm increased significantly in AWBP under PK addition. There was no effect of nutrient addition associated with either smaller (1 – 10 cm dbh) or larger trees (dbh > 30 cm). The medium-sized trees which may have experienced resource competition but have now transitioned into the canopy layer (exposed to sunlight) are able to use additional nutrient for active growth. In contrast, bigger trees may allocate extra nutrient for reproduction and leaf-vitality, while smaller trees remain shaded, co-limited by sunlight and therefore unable to utilize increased available nutrients for stem diameter growth. ANPP increased by 39% with N addition and marginally by 23% with K additions relative to the control. In conclusion, our experiment provides evidence of N and potentially K limitation of ANPP in this lower-montane tropical forest, and highlights that, in a highly diverse ecosystem different components of ANPP may be regulated by multiple nutrients. </p>

Early vegetation recovery and element cycles on a clear-cut watershed in western Oregon

1985 ◽  
Vol 15 (2) ◽  
pp. 400-409 ◽  
Author(s):  
Henry L. Gholz ◽  
Glenn M. Hawk ◽  
Alsie Campbell ◽  
Kermit Cromack Jr. ◽  
Alfred T. Brown
Keyword(s):  
Primary Production ◽  
Aboveground Biomass ◽  
Riparian Zone ◽  
Net Primary Production ◽  
Nutrient Loss ◽  
Litter Fall ◽  
Aboveground Net Primary Production ◽  
Clear Cut ◽  
Clear Cutting ◽  
Woody Shrubs

Aboveground biomass and leaf area, net primary production, and nutrient cycling through vegetation were studied for 3 years after clear-cutting (stems only) of a 10.24-ha watershed in the Oregon Cascade Mountains. The riparian zone and four main habitats were analyzed separately. In 3 years, aboveground net primary production increased from 5 to 112 g•m−2•year−1 in the ridgetop habitat; midsummer aboveground biomass increased from 8 to 196 g/m2 in the riparian zone and from 198 to 327 g/m2 on the ridgetop. Other values were intermediate to these. Litter fall of species with perennial aboveground parts averaged 20–27% of standing biomass. Native annuals, especially Araliacalifornica Wats., dominated the riparian zone. Seneciosylvaticus L., an introduced species, dominated most of the rest of the watershed, except for the ridgetop habitat, which was dominated by residual woody shrubs. Uptake of N exceeded losses in streamflow the 1st year and was six times greater in the 2nd; uptake of P and K in that year was 2.5 and 3 times greater than losses. In the 3rd year, total uptake of K (2.5 g•m−2•year−1) equaled the preclear-cutting level, and uptake of N (1.3 g•m−2•year−1) and P (0.3 g•m−2•year−1) was about half that level. No correlation was found between plant uptake and nutrient loss in streamflow. Uptake of all elements exceeded return through leaching and litter fall by 16%, except that of Mg, which exceeded return by 44%. Because of early dominance by species with annuals, the proportion of elements redistributed internally by vegetation was generally low. The amount of nutrients in flux through vegetation, atmosphere, and stream was small in comparison to the amount lost in the removal of tree stems.

Early effect of elevated nitrogen input on above-ground net primary production of a lower montane rain forest, Panama

2009 ◽  
Vol 25 (6) ◽  
pp. 637-647 ◽  
Author(s):  
Markus Adamek ◽  
Marife D. Corre ◽  
Dirk Hölscher
Keyword(s):  
Primary Production ◽  
Rain Forest ◽  
Net Primary Production ◽  
Woody Biomass ◽  
N Fertilization ◽  
Stem Growth ◽  
First Year ◽  
N Addition ◽  
Montane Rain Forest ◽  
Stem Diameter Growth

Abstract:To evaluate N limitation on above-ground net primary production in a tropical lower montane rain forest, an N fertilization experiment was conducted for 2 y. The study site is located at 1200–1300 m asl in the Fortuna forest reserve in western Panama and has a mature, mixed-species stand growing on an Andisol soil. Control and N-fertilized (125 kg urea-N ha−1 y−1) treatments were represented by four replicate plots (each 40 × 40 m, separated by at least 40 m). Stem diameter growth was analysed by diameter at breast height classes and also for the three most abundant species. The three species did not respond to N addition. The response of stem growth and above-ground woody biomass production to N fertilization varied among dbh classes. Stem growth of trees of 10–30 cm dbh increased only in the first year of N addition while trees of 30–50 cm dbh responded in the second year of N addition, which may be due to differences in light conditions between years. Trees >50 cm dbh did not respond during 2 years of N addition. As a result, the overall stem growth and above-ground woody biomass production were not affected by N fertilization. Annual total fine litterfall increased in the first year of N fertilization, while annual leaf litterfall increased in both years of N addition. Above-ground net primary production, of which total fine litterfall constituted 68%, also increased only in the first year of N addition. The magnitude and timing of response of stem diameter growth and litterfall suggest that these aspects of above-ground productivity are not uniformly limited by N availability.

scholarly journals Integration of Forest Growth Component in the FEST-WB Distributed Hydrological Model: The Bonis Catchment Case Study

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1794
Author(s):  
Mouna Feki ◽  
Giovanni Ravazzani ◽  
Alessandro Ceppi ◽  
Gaetano Pellicone ◽  
Tommaso Caloiero
Keyword(s):  
Primary Production ◽  
Hydrological Model ◽  
Carbon Allocation ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Forest Growth ◽  
Distributed Hydrological Model ◽  
Homogeneous Population ◽  
Forest Model ◽  
The Impact

In this paper, the FEST-FOREST model is presented. A FOREST module is written in the FORTRAN-90 programming language, and was included in the FEST-WB distributed hydrological model delivering the FEST-FOREST model. FEST-FOREST is a process-based dynamic model allowing the simulation at daily basis of gross primary production (GPP) and net primary production (NPP) together with the carbon allocation of a homogeneous population of trees (same age, same species). The model was implemented based on different equations from literature, commonly used in Eco-hydrological models. This model was developed within the framework of the INNOMED project co-funded under the ERA-NET WaterWorks2015 Call of the European Commission. The aim behind the implementation of the model was to simulate in a simplified mode the forest growth under different climate change and management scenarios, together with the impact on the water balance at the catchment. On a first application of the model, the results are considered very promising when compared to field measured data.

scholarly journals Prioritising Carbon Sequestration Areas in Southern Queensland using Time Series MODIS Net Primary Productivity (NPP) Imagery

2014 ◽  
Vol XL-8 ◽  
pp. 549-553
Author(s):  
A. Apan ◽  
L. A. Suarez Cadavid ◽  
L. Richardson ◽  
T. Maraseni
Keyword(s):  
Carbon Sequestration ◽  
Primary Production ◽  
Net Primary Productivity ◽  
Net Primary Production ◽  
Climate Scenario ◽  
Forest Growth ◽  
Tree Canopy ◽  
Annual Rainfall ◽  
Primary Input ◽  
Tree Canopy Cover

The aim of this study was to develop a method that will use satellite imagery to identify areas of high forest growth and productivity, as a primary input in prioritising revegetation sites for carbon sequestration. Using the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data, this study analysed the annual net primary production (NPP) values (gC/m<sup>2</sup>) of images acquired from 2000 to 2013, covering the Condamine Catchment in southeast Queensland, Australia. With the analysis of annual rainfall data during the same period, three transitions of "normal to dry" years were identified to represent the future climate scenario considered in this study. The difference in the corresponding NPP values for each year was calculated, and subsequently averaged to the get the "<i>Mean of Annual NPP Difference</i>" (MAND) map. This layer identified the areas with increased net primary production despite the drought condition in those years. Combined with key thematic maps (i.e. regional ecosystems, land use, and tree canopy cover), the priority areas were mapped. The results have shown that there are over 42 regional ecosystem (RE) types in the study area that exhibited positive vegetation growth and productivity despite the decrease in annual rainfall. However, seven (7) of these RE types represents the majority (79 %) of the total high productivity area. A total of 10,736 ha were mapped as priority revegetation areas. This study demonstrated the use of MODIS-NPP imagery to map vegetation with high carbon sequestration rates necessary in prioritising revegetation sites.

scholarly journals A Preliminary Study on the Net Primary Production of the Secondary Tropical Forest in Xishuangbanna

2003 ◽  
Vol 27 (6) ◽  
pp. 756-764
Author(s):  
TANG Jian-Wei ◽  
ZHANG Jian-Hou ◽  
SONG Qi-Shi ◽  
FENG Zhi-Li ◽  
DANG Cheng-Lin ◽  
...  
Keyword(s):  
Primary Production ◽  
Tropical Forest ◽  
Net Primary Production ◽  
Preliminary Study ◽  
Secondary Tropical Forest

NET PRIMARY PRODUCTION IN TROPICAL FORESTS: AN EVALUATION AND SYNTHESIS OF EXISTING FIELD DATA

2001 ◽  
Vol 11 (2) ◽  
pp. 371-384 ◽  
Author(s):  
Deborah A. Clark ◽  
Sandra Brown ◽  
David W. Kicklighter ◽  
Jeffrey Q. Chambers ◽  
John R. Thomlinson ◽  
...  
Keyword(s):  
Primary Production ◽  
Tropical Forests ◽  
Field Data ◽  
Net Primary Production

scholarly journals Aboveground Carbon Storage and Cycling of Flooded and Upland Forests of the Brazilian Pantanal

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 665
Author(s):  
Osvaldo Borges Pinto ◽  
Ana Carolina Amorim Marques ◽  
George L. Vourlitis
Keyword(s):  
Tropical Forests ◽  
Net Primary Production ◽  
Mixed Forest ◽  
Forest Litter ◽  
Litter Production ◽  
Wet Season ◽  
Flooded Forest ◽  
Sampling Campaign ◽  
Flooded Forests ◽  
Seasonally Flooded

Tropical forests and savanna (cerrado) are important carbon (C) sinks; however, few data exist for seasonally flooded forests. We quantified the annual rates of aboveground net primary production (ANPP) over a five-year period for two forests, an upland mixed forest and a seasonally flooded cerrado forest, located in the northern Pantanal region of Brazil. We hypothesized that rates of ANPP would be higher for the mixed forest than the cerrado forest because seasonal flooding can limit rates of tree growth. ANPP was calculated as the sum of the annual litter production measured from litterfall traps and the stem growth increment measured from dendrometers and tree density. ANPP varied between 3.8–5.5 MgC ha−1 y−1 for the flooded forest and 1.6–4.6 MgC ha−1 y−1 for the upland forest. Litter production accounted for 57% of the ANPP, and the difference in ANPP between the upland and flooded forests was due to consistently higher litter production in the flooded forest. Annual variations in ANPP were not correlated with annual precipitation, presumably because the hydrology of these sites is driven more by the flood stage of the Cuiaba River than by local precipitation. However, consistent declines in forest floor litter mass occurred at both sites, suggesting that C storage may be responding to some unknown disturbance that occurred prior to our sampling campaign. Seasonal variation in rainfall exerted an important control on litter production dynamics, with leaf litter production increasing during the dry season and stem and reproductive litter production increasing during the wet season. While there are few studies of seasonally flooded tropical forests, our data suggest that the seasonally flooded and upland forests of the northern Pantanal can act as appreciable aboveground C sinks.

scholarly journals Low and High Nitrogen Deposition Rates in Northern Coniferous Forests Have Different Impacts on Aboveground Litter Production, Soil Respiration, and Soil Carbon Stocks

Ecosystems ◽  
2020 ◽  
Vol 23 (7) ◽  
pp. 1423-1436 ◽  
Author(s):  
Benjamin Forsmark ◽  
Annika Nordin ◽  
Nadia I. Maaroufi ◽  
Tomas Lundmark ◽  
Michael J. Gundale
Keyword(s):  
Soil Respiration ◽  
Net Primary Production ◽  
N Deposition ◽  
Coniferous Forests ◽  
Organic Layer ◽  
Litter Production ◽  
N Addition ◽  
Mass Unit ◽  
Soil C ◽  
C Storage

AbstractNitrogen (N) deposition can change the carbon (C) sink of northern coniferous forests by changing the balance between net primary production and soil respiration. We used a field experiment in an N poor Pinus sylvestris forest where five levels of N (0, 3, 6, 12, and 50 kg N ha−1 yr−1, n = 6) had been added annually for 12–13 years to investigate how litter C inputs and soil respiration, divided into its autotrophic and heterotrophic sources, respond to different rates of N input, and its subsequent effect on soil C storage. The highest N addition rate (50 kg N ha−1 yr−1) stimulated soil C accumulation in the organic layer by 22.3 kg C kg−1 N added, increased litter inputs by 46%, and decreased soil respiration per mass unit of soil C by 31.2%, mainly by decreasing autotrophic respiration. Lower N addition rates (≤ 12 kg N ha−1 yr−1) had no effect on litter inputs or soil respiration. These results support previous studies reporting on increased litter inputs coupled to impeded soil C mineralization, contributing to enhancing the soil C sink when N is supplied at high rates, but add observations for lower N addition rates more realistic for N deposition. In doing so, we show that litter production in N poor northern coniferous forests can be relatively unresponsive to low N deposition levels, that stimulation of microbial activity at low N additions is unlikely to reduce the soil C sink, and that high levels of N deposition enhance the soil C sink by increasing litter inputs and decreasing soil respiration.

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