scholarly journals Do increasing respiratory costs explain the decline with age of forest growth rate?

2019 ◽  
Vol 31 (3) ◽  
pp. 693-712 ◽  
Author(s):  
P. W. West
Keyword(s):  
Growth Rate ◽  
Water Stress ◽  
Primary Production ◽  
Fine Roots ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Forest Growth ◽  
Mean Annual Temperature ◽  
Data Set ◽  
Wide Range

Abstract Once forests have achieved a full canopy, their growth rate declines progressively with age. This work used a global data set with estimates from a wide range of forest types, aged 20‒795 years, of their annual photosynthetic production (gross primary production, GPP) and subsequent above- plus below-ground biomass production (net primary production, NPP). Both GPP and NPP increased with increasing mean annual temperature and precipitation. GPP was then unrelated to forest age whilst NPP declined progressively with increasing age. These results implied that autotrophic respiration increases with age. It has been proposed that GPP should decline in response to increasing water stress in leaves as water is raised to greater heights as trees grow taller with age. However, trees may make substantial plastic adjustment in morphology and anatomy of newly developing leaves, xylem and fine roots to compensate for this stress and maintain GPP with age. This work reviews the possibilities that NPP declines with age as respiratory costs increase progressively in, any or all of, the construction and maintenance of more complex tissues, the maintenance of increasing amounts of live tissue within the sapwood of stems and coarse roots, the conversion of sapwood to heartwood, the increasing distance of phloem transport, increased turnover rates of fine roots, cost of supporting very tall trees that are unable to compensate fully for increased water stress in their canopies or maintaining alive competitively unsuccessful small trees.

scholarly journals Experimental assessment of the sensitivity of an estuarine phytoplankton fall bloom to acidification and warming

2018 ◽  
Vol 15 (16) ◽  
pp. 4883-4904 ◽  
Author(s):  
Robin Bénard ◽  
Maurice Levasseur ◽  
Michael Scarratt ◽  
Marie-Amélie Blais ◽  
Alfonso Mucci ◽  
...  
Keyword(s):  
Growth Rate ◽  
Primary Production ◽  
Net Primary Production ◽  
Skeletonema Costatum ◽  
Potential Effect ◽  
Lawrence Estuary ◽  
Chl A ◽  
Wide Range ◽  
To Come ◽  
St Lawrence Estuary

Abstract. We investigated the combined effect of ocean acidification and warming on the dynamics of the phytoplankton fall bloom in the Lower St. Lawrence Estuary (LSLE), Canada. Twelve 2600 L mesocosms were set to initially cover a wide range of pHT (pH on the total proton scale) from 8.0 to 7.2 corresponding to a range of pCO2 from 440 to 2900 µatm, and two temperatures (in situ and +5 ∘C). The 13-day experiment captured the development and decline of a nanophytoplankton bloom dominated by the chain-forming diatom Skeletonema costatum. During the development phase of the bloom, increasing pCO2 influenced neither the magnitude nor the net growth rate of the nanophytoplankton bloom, whereas increasing the temperature by 5 ∘C stimulated the chlorophyll a (Chl a) growth rate and maximal particulate primary production (PP) by 76 % and 63 %, respectively. During the declining phase of the bloom, warming accelerated the loss of diatom cells, paralleled by a gradual decrease in the abundance of photosynthetic picoeukaryotes and a bloom of picocyanobacteria. Increasing pCO2 and warming did not influence the abundance of picoeukaryotes, while picocyanobacteria abundance was reduced by the increase in pCO2 when combined with warming in the latter phase of the experiment. Over the full duration of the experiment, the time-integrated net primary production was not significantly affected by the pCO2 treatments or warming. Overall, our results suggest that warming, rather than acidification, is more likely to alter phytoplankton autumnal bloom development in the LSLE in the decades to come. Future studies examining a broader gradient of temperatures should be conducted over a larger seasonal window in order to better constrain the potential effect of warming on the development of blooms in the LSLE and its impact on the fate of primary production.

scholarly journals Primary production in forests and grasslands of China: contrasting environmental responses of light- and water-use efficiency models

2012 ◽  
Vol 9 (4) ◽  
pp. 4285-4321 ◽  
Author(s):  
H. Wang ◽  
I. C. Prentice ◽  
J. Ni
Keyword(s):  
Primary Production ◽  
Water Use Efficiency ◽  
Water Use ◽  
South China ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Stomatal Closure ◽  
Co2 Response ◽  
Data Set ◽  
Use Efficiency

Abstract. An extensive data set on net primary production (NPP) in China's forests is analysed with two semi-empirical models based on the light use efficiency (LUE) and water use efficiency (WUE) concepts, respectively. Results are shown to be broadly consistent with other data sets (grassland above-ground NPP; globally extrapolated gross primary production, GPP) and published analyses. But although both models describe the data about equally well, they predict notably different responses to [CO2] and temperature. These are illustrated by sensitivity tests in which [CO2] is kept constant or doubled, temperatures are kept constant or increased by 3.5 K, and precipitation is changed by ±10%. Precipitation changes elicit similar responses in both models. The [CO2] response of the WUE model is much larger but is probably an overestimate for dense vegetation as it assumes no increase in runoff; while the [CO2] response of the LUE model is probably too small for sparse vegetation as it assumes no increase in vegetation cover. In the LUE model warming reduces total NPP with the strongest effect in South China, where the growing season cannot be further extended. In the WUE model warming increases total NPP, again with the strongest effect in South China, where abundant water supply precludes stomatal closure. The qualitative differences between the two formulations illustrate potential causes of the large differences (even in sign) in the global NPP response of dynamic global vegetation models to [CO2] and climate change. As it is not clear which response is more realistic, the issue needs to be resolved by observation and experiment.

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.

Energy and nutrients

2019 ◽  
pp. 161-176
Author(s):  
Richard T. Corlett
Keyword(s):  
Primary Production ◽  
Forest Ecology ◽  
Net Primary Production ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Nitrogen And Phosphorus ◽  
New Information ◽  
Tropical Forest Ecology ◽  
Toxic Concentrations

This chapter deals with the ecology of Tropical East Asia from the perspective of water, energy, and matter flows through ecosystems, particularly forests. Data from the network of eddy flux covariance towers is revealing general patterns in gross primary production, ecosystem respiration, and net ecosystem production, and exchange. There is also new information on the patterns of net primary production and biomass within the region. In contrast, our understanding of the role of soil nutrients in tropical forest ecology still relies mostly on work done in the Neotropics, with just enough data from Asia to suggest that the major patterns may be pantropical. Nitrogen and phosphorus have received most attention regionally, followed by calcium, potassium, and magnesium, and there has been very little study of the role of micronutrients and potentially toxic concentrations of aluminium, manganese, and hydrogen ions. Animal nutrition has also been neglected.

scholarly journals How drought severity constrains gross primary production(GPP) and its partitioning among carbon pools in a <i>Quercus ilex</i> coppice?

2014 ◽  
Vol 11 (23) ◽  
pp. 6855-6869 ◽  
Author(s):  
S. Rambal ◽  
M. Lempereur ◽  
J. M. Limousin ◽  
N. K. Martin-StPaul ◽  
J. M. Ourcival ◽  
...  
Keyword(s):  
Primary Production ◽  
Water Deficit ◽  
Eddy Covariance ◽  
Quercus Ilex ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Carbon Fluxes ◽  
Stem Growth ◽  
Drought Severity ◽  
Mediterranean Ecosystem

Abstract. The partitioning of photosynthates toward biomass compartments plays a crucial role in the carbon (C) sink function of forests. Few studies have examined how carbon is allocated toward plant compartments in drought-prone forests. We analyzed the fate of gross primary production (GPP) in relation to yearly water deficit in an old evergreen Mediterranean Quercus ilex coppice severely affected by water limitations. Carbon fluxes between the ecosystem and the atmosphere were measured with an eddy covariance flux tower running continuously since 2001. Discrete measurements of litterfall, stem growth and fAPAR allowed us to derive annual productions of leaves, wood, flowers and acorns, and an isometric relationship between stem and belowground biomass has been used to estimate perennial belowground growth. By combining eddy covariance fluxes with annual net primary productions (NPP), we managed to close a C budget and derive values of autotrophic, heterotrophic respirations and carbon-use efficiency (CUE; the ratio between NPP and GPP). Average values of yearly net ecosystem production (NEP), GPP and Reco were 282, 1259 and 977 g C m−2. The corresponding aboveground net primary production (ANPP) components were 142.5, 26.4 and 69.6 g C m−2 for leaves, reproductive effort (flowers and fruits) and stems, respectively. NEP, GPP and Reco were affected by annual water deficit. Partitioning to the different plant compartments was also impacted by drought, with a hierarchy of responses going from the most affected – the stem growth – to the least affected – the leaf production. The average CUE was 0.40, which is well in the range for Mediterranean-type forest ecosystems. CUE tended to decrease less drastically in response to drought than GPP and NPP did, probably due to drought acclimation of autotrophic respiration. Overall, our results provide a baseline for modeling the inter-annual variations of carbon fluxes and allocation in this widespread Mediterranean ecosystem, and they highlight the value of maintaining continuous experimental measurements over the long term.

scholarly journals Carbon Balance in Salt Marsh and Mangrove Ecosystems: A Global Synthesis

2020 ◽  
Vol 8 (10) ◽  
pp. 767 ◽  
Author(s):  
Daniel M. Alongi
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Salt Marshes ◽  
Dissolved Inorganic Carbon ◽  
Net Primary Production ◽  
Ecosystem Respiration ◽  
Soil Depth ◽  
Gross Primary Production ◽  
Coastal Ocean ◽  
Microbial Decomposition

Mangroves and salt marshes are among the most productive ecosystems in the global coastal ocean. Mangroves store more carbon (739 Mg CORG ha−1) than salt marshes (334 Mg CORG ha−1), but the latter sequester proportionally more (24%) net primary production (NPP) than mangroves (12%). Mangroves exhibit greater rates of gross primary production (GPP), aboveground net primary production (AGNPP) and plant respiration (RC), with higher PGPP/RC ratios, but salt marshes exhibit greater rates of below-ground NPP (BGNPP). Mangroves have greater rates of subsurface DIC production and, unlike salt marshes, exhibit active microbial decomposition to a soil depth of 1 m. Salt marshes release more CH4 from soil and creek waters and export more dissolved CH4, but mangroves release more CO2 from tidal waters and export greater amounts of particulate organic carbon (POC), dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), to adjacent waters. Both ecosystems contribute only a small proportion of GPP, RE (ecosystem respiration) and NEP (net ecosystem production) to the global coastal ocean due to their small global area, but contribute 72% of air–sea CO2 exchange of the world’s wetlands and estuaries and contribute 34% of DIC export and 17% of DOC + POC export to the world’s coastal ocean. Thus, both wetland ecosystems contribute disproportionately to carbon flow of the global coastal ocean.

Testing across vegetation types for common environmental dependencies of Gross Primary Production

2020 ◽  
Author(s):  
Keith Bloomfield ◽  
Benjamin Stocker ◽  
Colin Prentice
Keyword(s):  
Soil Moisture ◽  
Primary Production ◽  
Eddy Covariance ◽  
Empirical Analysis ◽  
Gross Primary Production ◽  
Incident Light ◽  
Vapour Pressure Deficit ◽  
Additive Models ◽  
Theoretical Modelling ◽  
Wide Range

&lt;p&gt;Accurate simulations of gross primary production (GPP) are vital for Earth System Models that must inform public policy decisions. &amp;#160;The instantaneous controls of leaf-level photosynthesis, which can be measured in manipulative experiments, are well established. &amp;#160;At the canopy scale, however, there is no consensus on how GPP depends on (a) light or (b) other aspects of the physical environment such as temperature and CO&lt;sub&gt;2&lt;/sub&gt;. &amp;#160;Models of GPP make a variety of different assumptions when &amp;#8216;scaling-up&amp;#8217; the standard model of photosynthesis. &amp;#160;As a troublesome consequence, they make a variety of different predictions about how GPP responds to contemporary environmental change.&lt;/p&gt;&lt;p&gt;This problem can be tackled by theoretically based modelling, or by empirical analysis of GPP as reconstructed from eddy-covariance flux measurements. &amp;#160;Theoretical modelling has provided an explanation for why &amp;#8216;light-use efficiency&amp;#8217; (LUE) models work well at time scales of a week or longer. &amp;#160;The same logic provides a justification for the use of LUE as a key metric in an empirical analysis. &amp;#160;By focusing on LUE, we can isolate the controls of GPP that are distinct from its over-riding control by absorbed light. &amp;#160;We have used open-access eddy covariance data from over 100 sites, collated over 20 years (the number of sites has grown with time). &amp;#160;These sites, located in a wide range of biomes and climate zones, form part of the FLUXNET network. &amp;#160;We have combined the flux data with a satellite product (FPAR from MODIS) that provides spatial estimates of the fraction of incident light absorbed by green vegetation. &amp;#160;Soil moisture at flux sites was estimated using the SPLASH model, with appropriate meteorological inputs, and soil water-holding capacity derived using SoilGrids. &amp;#160;LUE was then calculated as the amount of carbon fixed per unit of absorbed light. &amp;#160;We then considered additive models (incorporating multiple explanatory factors) that support non-linear responses, including a peaked response to temperature. &amp;#160;Recognising that our longitudinal data are not fully independent, we controlled for the hierarchical nature of the dataset through a variance structure that nests measurement year within site location.&lt;/p&gt;&lt;p&gt;In arriving at a final parsimonious model, we show that daytime air temperature and vapour pressure deficit, and soil moisture content, are all salient predictors of LUE. &amp;#160;The same explanatory terms are retained in iterations of this analysis run at timescales from weeks to months. &amp;#160;Model performance was not significantly improved by inclusion of additional variables such as rainfall, site elevation or vegetation category (e.g. Plant Functional Type, PFT). &amp;#160;This empirical analysis supports the notion that GPP is predictable using a single model structure that is common to different PFTs.&lt;/p&gt;

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

&lt;p&gt;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&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;, 50 kg P ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt; and 50 kg K ha&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;We established 32 (8 treatments &amp;#215; 4 replicates) experimental plots of 40 &amp;#215; 40 m&lt;sup&gt;2&lt;/sup&gt; each and measured stem growth of over 15,000 trees with diameter at breast height (dbh) &amp;#8805; 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.&lt;/p&gt;&lt;p&gt;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 &amp;#177; 1.4 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) and K (13.3 &amp;#177; 1.8 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) addition plots than the control (11.1 &amp;#177; 0.6 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) 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 &amp;#8211; 30 cm increased significantly in AWBP under PK addition. There was no effect of nutrient addition associated with either smaller (1 &amp;#8211; 10 cm dbh) or larger trees (dbh &gt; 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.&amp;#160;&lt;/p&gt;

Changes in biomass and production over 53 years in a coastal Piceasitchensis –Tsugaheterophylla forest approaching maturity

1990 ◽  
Vol 20 (10) ◽  
pp. 1602-1610 ◽  
Author(s):  
P. A. Harcombe ◽  
Mark E. Harmon ◽  
Sarah E. Greene
Keyword(s):  
Primary Production ◽  
Fine Roots ◽  
Net Primary Production ◽  
Forest Biomass ◽  
Biomass Accumulation ◽  
Maintenance Respiration ◽  
Bole Biomass

Using periodic remeasurements of tagged trees in nine 0.4-ha sample plots in a Piceasitchensis (Bong.) Carr. – Tsugaheterophylla (Raf.) Sarg. forest at Cascade Hand Experimental Forest, Oregon, we calculated that biomass of bolewood increased from 570 Mg•ha−1 at age 85 years to 760 Mg•ha−1 at age 138 years. Net primary production of bolewood declined from 11 to about 6 Mg•ha−1•year−1, and mortality loss increased from 2 to about 6 Mg•ha−1•year−1. Values for 37-year-old plots in the same area were 210–360 Mg•ha−1•year−1 bole biomass, 7–20 Mg•ha−1•year−1 bolewood production, and 0–2 Mg•ha−1•year−1 mortality loss. Indications are that bolewood production and biomass were lower in the older plots when they were 37 years old. In the older plots, biomass did not increase between ages 120 and 138. Of the photosynthate potentially available for bolewood production, some replaces biomass lost via mortality and some is allocated to maintenance (respiration plus allocation to fine roots). We estimate that one-quarter to one-half of the production is lost by mortality, and that mortality loss may thus be an important factor limiting forest biomass accumulation.

Variability in carbon exchange and light utilization among boreal forest stands: implications for remote sensing of net primary production

1998 ◽  
Vol 28 (3) ◽  
pp. 375-389 ◽  
Author(s):  
Scott J Goetz ◽  
Stephen D Prince
Keyword(s):  
Remote Sensing ◽  
Primary Production ◽  
Boreal Forest ◽  
Populus Tremuloides ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Total Carbon ◽  
Simple Relationship ◽  
Carbon Exchange ◽  
Forest Stands

Variability in carbon exchange, net primary production (NPP), and light-use efficiency were explored for 63 boreal forest stands in northeastern Minnesota using an ecophysiological model. The model was initialized with extensive field measurements of Populus tremuloides Michx. and Picea mariana (Mill.) BSP stand properties. The results showed that the proportion of total carbon assimilation expended in autotrophic respiration (i.e., the respiration to assimilation ratio, R/A) was significantly different for the two tree species and this explained much of the variability in the amount of net production per unit absorbed photosynthetically active radiation (APAR), referred to as PAR utilization ( epsilonn). This is the first known study to directly link variability in respiratory costs to epsilonn. Total assimilation per unit APAR ( epsilong) was much less variable than epsilonn and was not significantly different between species. Greater stomatal control on some moisture stressed sites accounted for most of the variability in epsilong. The lack of a simple relationship between light harvesting and net carbon gain indicates that estimation of net primary production with satellite remote sensing requires additional information on respiration costs; however, evidence for convergence in epsilong can be used to simplify the remote sensing of gross primary production over large areas.

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