Hydrology-oriented (adaptive) silviculture in a semiarid pine plantation: How much can be modified the water cycle through forest management?

del Campo, A. D., et al., 2014. European Journal of Forest Research

Original research (primary data)
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Abstract

Hydrology-oriented silviculture might adapt Mediterranean forests to climatic changes, although its implementation demands a better understanding and quantification on the water fluxes. The influence of thinning intensity (high, medium, low and a control) and its effect on the mid-term (thinned plots in 1998 and 2008) on the water cycle (transpiration, soil water and interception) and growth [basal area increment (BAI)] were investigated in 55-year-old Aleppo pine trees. Thinning enhanced a lower dependence of growth on climate fluctuations. The high-intensity treatment showed significant increases in the mean annual BAI (from 4.1 to 17.3 cm(2)) that was maintained in the mid-term. Thinning intensity progressively increased the sap flow velocity (v (s)) in all cases with respect to the control. In the mid-term, an increased functionality of the inner sapwood was also observed. Mean daily tree water use ranged from 5 (control) to 18 (high intensity) l tree(-1). However, when expressed on an area basis, daily transpiration ranged from 0.18 (medium) to 0.30 mm (control), meaning that in spite of the higher transpiration rates in the remaining trees, stand transpiration was reduced with thinning. Deep infiltration of water was also enhanced with thinning (about 30 % of rainfall) and did not compete with transpiration, as both presented opposite seasonal patterns. The changes in the stand water relationships after 10 years were well explained by the forest cover metric. The blue to green water ratio changed from 0.15 in the control to 0.72 in the high-intensity treatment, with the remaining treatments in the 0.34-0.48 range.

Case studies

Basic information

  • Case ID: INT-074-1
  • Intervention type: Management
  • Intervention description:

    Field experiment. intervention – adaptive hydrology-oriented silviculture/proactive adaptive management to either maintain or to gradually adapt current forest ecosystems to precipitation decrease and evapotranspiration increase due to climate change management of P. halepensis plantations; still considered NBS because “The improvement in site conditions (microclimate and soil properties) brought by the pine forests is expected to trigger late-successional species to spontaneously establish and to stimulate the ecosystem towards a more mature stage.” specifically the intervention involves thinning at different intensities [low, med, high]. Thinning removed the less developed trees and was performed to achieve a relatively homogeneous tree distribution (based on forest cover) in the plots

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Reduced water availability  Positive water availability – green/blue water ratio (to determine about of blue water i.e. that not taken up by plants and released through evapotranspiration) soil water content - The SWC (m3 m-3) was continuously measured for the whole period in all treatments every 20 min by means of FDR sensors (EC-TM, Decagon Devices Inc., Pullman, WA) connected to several EM50 (Decagon) dataloggers.
  • Approach implemented in the field: Yes
  • Specific location:

    planted pine forest located in the southwest region of Valencia province in Spain (39 0503000N, 1 1203000W) at 950 m a.s.l

  • Country: Spain
  • Habitat/Biome type: Temperate forests |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: The vegetation structure of this site is quite simple, with little importance of the understory (even in the 1998 thinning, where scrub weeding is accomplished regularly) meaning that translating these results to other forest plantations need caution. Thinning enhanced a lower dependence of growth on climate fluctuations; which means that it not only increases water availability but makes these forest stands more resilience to climate fluctuations. Bottom line - Thinning increases water availability (blue water) because it reduces stand transpiration, reduces rainfall interception, and increases deep infiltration of water (I think)
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures:
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: