Fertilization increases sensitivity of canopy stomatal conductance and transpiration to throughfall reduction in an 8-year-old loblolly pine plantation

2015 ◽  
Vol 354 ◽  
pp. 87-96 ◽  
Author(s):  
Stan M. Bartkowiak ◽  
Lisa J. Samuelson ◽  
Mary Anne McGuire ◽  
Robert O. Teskey
Keyword(s):  
Stomatal Conductance ◽  
Loblolly Pine ◽  
Pine Plantation ◽  
Canopy Stomatal Conductance ◽  
Throughfall Reduction

scholarly journals Stomatal conductance limited the CO2 response of grassland in the last century

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Juan C. Baca Cabrera ◽  
Regina T. Hirl ◽  
Rudi Schäufele ◽  
Andy Macdonald ◽  
Hans Schnyder
Keyword(s):  
Climate Change ◽  
Stomatal Conductance ◽  
Nitrogen Nutrition ◽  
Physiological Control ◽  
Co2 Response ◽  
Nitrogen Acquisition ◽  
Wide Range ◽  
Park Grass Experiment ◽  
Conductance Changes ◽  
Canopy Stomatal Conductance

Abstract Background The anthropogenic increase of atmospheric CO2 concentration (ca) is impacting carbon (C), water, and nitrogen (N) cycles in grassland and other terrestrial biomes. Plant canopy stomatal conductance is a key player in these coupled cycles: it is a physiological control of vegetation water use efficiency (the ratio of C gain by photosynthesis to water loss by transpiration), and it responds to photosynthetic activity, which is influenced by vegetation N status. It is unknown if the ca-increase and climate change over the last century have already affected canopy stomatal conductance and its links with C and N processes in grassland. Results Here, we assessed two independent proxies of (growing season-integrating canopy-scale) stomatal conductance changes over the last century: trends of δ18O in cellulose (δ18Ocellulose) in archived herbage from a wide range of grassland communities on the Park Grass Experiment at Rothamsted (U.K.) and changes of the ratio of yields to the CO2 concentration gradient between the atmosphere and the leaf internal gas space (ca – ci). The two proxies correlated closely (R2 = 0.70), in agreement with the hypothesis. In addition, the sensitivity of δ18Ocellulose changes to estimated stomatal conductance changes agreed broadly with published sensitivities across a range of contemporary field and controlled environment studies, further supporting the utility of δ18Ocellulose changes for historical reconstruction of stomatal conductance changes at Park Grass. Trends of δ18Ocellulose differed strongly between plots and indicated much greater reductions of stomatal conductance in grass-rich than dicot-rich communities. Reductions of stomatal conductance were connected with reductions of yield trends, nitrogen acquisition, and nitrogen nutrition index. Although all plots were nitrogen-limited or phosphorus- and nitrogen-co-limited to different degrees, long-term reductions of stomatal conductance were largely independent of fertilizer regimes and soil pH, except for nitrogen fertilizer supply which promoted the abundance of grasses. Conclusions Our data indicate that some types of temperate grassland may have attained saturation of C sink activity more than one century ago. Increasing N fertilizer supply may not be an effective climate change mitigation strategy in many grasslands, as it promotes the expansion of grasses at the disadvantage of the more CO2 responsive forbs and N-fixing legumes.

Assessment of canopy stomatal conductance models using flux measurements

2009 ◽  
Vol 220 (17) ◽  
pp. 2115-2118 ◽  
Author(s):  
Shusen Wang ◽  
Yan Yang ◽  
Alexander P. Trishchenko
Keyword(s):  
Stomatal Conductance ◽  
Flux Measurements ◽  
Canopy Stomatal Conductance

scholarly journals Dual-Cropping Loblolly Pine for Biomass Energy and Conventional Wood Products

2008 ◽  
Vol 32 (1) ◽  
pp. 33-37 ◽  
Author(s):  
D. Andrew Scott ◽  
Allan Tiarks
Keyword(s):  
Loblolly Pine ◽  
Small Diameter ◽  
Cropping System ◽  
N Fertilization ◽  
Wood Products ◽  
Biomass Energy ◽  
Pine Plantation ◽  
Southern Pine ◽  
Small Diameter Trees ◽  
Viable Method

Abstract Southern pine stands have the potential to provide significant feedstocks for the growing biomass energy and biofuel markets. Although initial feedstocks likely will come from low-value small-diameter trees, understory vegetation, and slash, a sustainable and continuous supply of biomass is necessary to support and grow a wood bioenergy market. As long as solidwood products are more valuable, bioenergy production will not be the primary market for southern pine. A study exploring a dual-cropping system for southern pine bioenergy and solidwood products was begun in 1982 in Louisiana to determine the phosphorus (P) nutritional requirements of the system. Fertilization of 60 kg ha−1 of P was required to produce 90% of the maximum volume at the age of 22 years. Direct-seeding pine in the interrows of a traditional pine plantation produced about 10.2 Mg ha−1 of biomass for energy at the age of 5 years but had no lasting effect on the planted pine height, diameter, or standing volume. The system is a viable method to produce both bioenergy and solidwood products. Herbaceous competition control and nitrogen (N) fertilization likely would make the system even more productive and profitable.

scholarly journals Tree-Length System Evaluation of Second Thinning in a Loblolly Pine Plantation

2003 ◽  
Vol 27 (2) ◽  
pp. 77-82 ◽  
Author(s):  
Rien Visser ◽  
Karl Stampfer
Keyword(s):  
North Carolina ◽  
Loblolly Pine ◽  
System Evaluation ◽  
Field Observations ◽  
Pine Plantation ◽  
Piece Size ◽  
Tree Length ◽  
Study Methodology ◽  
Standing Timber ◽  
The Given

Abstract A productivity study and system evaluation was carried out on a tree-length operation working in a second thinning of loblolly pine near Greenville, North Carolina. The average tree volume was 8.1 ft3 and the average dbh was 8.4 in. The machines studied in the system were the Tigercat 720B feller-buncher, the Tigercat 630 skidder, and the tracked loader Tigercat 245. The goal was to reduce the standing timber from 225 trees/ac down to 92. Standard time-study methodology and multivariance statistical analyses were used to capture and evaluate the data. The key productivity parameters identified for the feller-buncher was piece volume and number of trees in the bunch, and for the skidder extraction distance, average piece volume and number of bunches picked up to make a turn. The ability of the loader to process increasing number of trees as average tree volume decreased, and the increased difficulty of delimbing the larger trees resulted in no significant variance for average piece size. Productivity functions were developed for the feller-buncher and the skidder. The system evaluation discusses the productivity balance between the machines for the given range of piece size as well as potential operational improvements based on in-field observations. South. J. Appl. For. 27(2):77–82.

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