Above- and below-ground biomass, surface and volume, and stored water in a mature Scots pine stand

Abstract

This study describes the amount and the spatial distribution of the above-and below-ground tree skeletondefined as the woody structure of stem, branches and rootsin a mature Scots pine (Pinus sylvestris L.) stand in Belgium. Tree skeleton data were linked to the respective needle area, and as such, this work provides the background framework for modeling the tree hydraulic architecture and the carbon balance of the forest stand. Using validated allometric equations, we were able to calculate the amount of the volume, of the biomass and of the corresponding surface areas of individual trees in the stand. Total woody biomass of the 66-year-old forest stand was 155 Mg ha -1 , i.e., 126 Mg ha -1 above ground and 29 Mg ha -1 below ground. The total bio-volume of the woody mass of the stand was 314 m 3 ha -1 . The highest fraction of this value was the stem bio-volume, i.e., 236 m 3 ha -1 or 75 % of the total. The total volume of all roots was 57 m 3 ha -1 (18 % of the total volume), and the volume of branches was 20 m 3 ha -1 (7 % of the total volume). The surface area of the roots ranged from 38,000 m 2 ha -1 in the winter to 68,000 m 2 ha -1 in the spring. The surface area of the stems was 2,700 m 2 ha -1 , and the surface area of all branches reached 4,400 m 2 ha -1 . The total above-ground water storage in the xylem was 94 m 3 ha -1 (or 9.4 mm), while the accessible stored water was 2 mm of that quantity. A comparative analysis of the biometric parameters showed the balance between the different functionally connected, operational surface areas of the trees. The needle surface area was similar to the root surface area and in the same order of magnitude as the surface area of woody cambium. The results allow to link water uptake with transpiration and assimilation with respiration.

Using isotopes to incorporate tree water storage and mixing dynamics into a distributed ecohydrologic modelling framework

“…As demonstrated by Phillips et al (), Köcher et al (), Čermák et al (), and Urban et al (), same‐day RWU is the major contributor to daily transpiration of both coniferous and deciduous trees during the growing season in temperate and Mediterranean climates, whereas the tree‐storage contribution during periods of low transpiration can be much larger (Hao et al, ). We anticipate that the simplification obtained by assuming ZS (and therefore EMMA methodologies for estimating RWU depths) would be most valid during periods of high transpiration and at locations with high soil water contents, whereas errors would grow at upslope locations and during periods of reduced soil water availability.…”

“…Further, EMMA requires the assumption that the measured isotopic compositions of xylem waters (δ XYLEM ) are representative of the RWU isotopic composition (δ RWU ), suggesting that water storage and mixing within trees is negligible. However, experimental studies of residence times within trees challenge this assumption (Čermák, Kučera, Bauerle, Phillips, & Hinckley, 2007;Köcher, Horna, Beckmeyer, & Leuschner, 2012;Meinzer et al, 2006;Urban, Čermák, & Ceulemans, 2015).…”

“…Capacitive discharge (forced transpiration from tree-stored water) provides a biological resilience against embolism (Scholz, Phillips, Bucci, Meinzer, & Goldstein, 2011). Tree-stored water has been shown to contribute up to 20% of daily transpiration during the peak growing season within Douglas fir (Pseudotsuga menziesii) in a Mediterranean climate (Čermák et al, 2007;Phillips et al, 2003), the genera Fagus, Tilia, Carpinus, Fraxinus, and Acer within a temperate climate (Köcher et al, 2012), and Scots pine (Pinus sylvestris) in a temperate maritime climate (Urban et al, 2015). Within time periods of reduced plant growth and atmospheric water demand, transpiration from Douglas fir can be sourced solely from tree-stored water for up to 1 week (Čermák et al, 2007).…”

Open field-applicable instrumental methods for structural and functional assessment of whole trees and stands

“…This means smaller parts of trees (e.g., branches from thicker ones to shoots), but especially their physical parameters as surface area and water content. Such studies are not so frequent (e.g., Kravka et al 1999, Honzová & Cermák 2012, Urban et al 2014, but represent important results and non-traditional information (e.g., cambium area index, CAI, or CAI/LAI, etc. - Fig.…”

Analysis of biomass in young Scots pine stands as a basis for sustainable forest management in Czech lowlands

“…Besides silvicultural effects on growth and stability of pine stands, water status and nutrient cycles (Chroust 1997;Sariyildiz 2008;Saarsalmi et al 2010;Slodičák et al 2011;Urban et al 2015), growth of pine seedlings after the site preparation ) and amounts of biomass ( Vanninen et al 1996;Cienciala et al 2006;Repola, Ulvcrona 2014;Fernandez-Lacruz et al 2015;Urban et al 2015;Bílek et al 2016;Egnell 2016) in managed stands are in the research focus.…”