2010年-世界发展银行全球_Forest_Restoration_Following_Earthquake_Damage_8页_691kb

EAP DRM KnowledgeNotes Summary: Forest Restoration Following Earthquake Damage

Core Content

This document outlines key considerations and strategies for forest restoration in the aftermath of the Wenchuan Earthquake, focusing on the East Asia and Pacific region, particularly China. It provides guidance on reforestation objectives, species selection, planting methods, site prioritization, and the importance of monitoring and adaptive management in post-disaster recovery.

Main Objectives of Reforestation

• Nature Reserves

  • Revegetate deforested areas with native plant species to restore original ecosystems.
  • Create self-sustaining mixtures of native and exotic species to stabilize landscapes and support wildlife.
  • Establish buffer zones around undisturbed areas to protect existing biota.
  • Build corridors between forest patches to allow wildlife movement.
  • Provide food plants for endangered, vulnerable, or rare species (e.g., bamboo for pandas).

• Undesignated Areas

  • Stabilize hill slopes to reduce landslides and erosion.
  • Create protective buffer strips along rivers and streams.
  • Establish commercially useful tree plantations for fuelwood or other goods.

Environmental Constraints

• Upper Landslide Areas

  • Lack topsoil and may have exposed subsoil or bedrock.
  • Infertile with low organic matter and soil seedbanks.
  • Require terracing, mounding, or fertilization to support plant growth.

• Lower Landslide Areas

  • May have accumulated topsoil but in an unconsolidated mix with subsoil.
  • Soil profile is spatially heterogeneous, with some areas more suitable for plant growth than others.

• Site Accessibility

  • Damage to roads and infrastructure may limit access to planting sites.
  • Sites far from intact forests may not benefit from natural seed dispersal by wildlife.

• Seed Requirements

  • Large quantities of planting materials are needed due to the scale of damage.
  • Early planning is essential to meet planting deadlines and ensure seed availability.

Species and Planting Materials Selection

• Types of Species

  • Fast-growing species for quick cover and bird perches.
  • Native broad-leaved trees to support wildlife habitats.
  • Shrubs to enhance structural complexity and soil protection.
  • Conifers for their site tolerance and economic value.
  • Deep-rooted species for slope stability.
  • Large-seeded species that require assistance for dispersal.
  • Nitrogen-fixers for soil enrichment.
  • Known food plants for wildlife (e.g., bamboo for pandas).
  • Fuelwood and other commercially attractive species.

• Planting Materials

  • Seedlings: Best for difficult sites due to mycorrhiza and Rhizobium inoculation. Efficient when seed supplies are limited.
  • Cuttings: Useful for species with limited seed availability (e.g., bamboo).
  • Direct Seeding: Suitable for inaccessible areas; requires high seed quantities and favorable conditions (e.g., low weed competition, no seed predators). May be less effective in soils lacking mycorrhiza.

Reforestation Methods

• Single Species Planting

  • Simple and common method.
  • Spacing of 3x3 meters is typical.
  • Denser plantings close canopy faster but are more costly.
  • Seedlings must be hardened off before planting.
  • Weeds need to be controlled until canopy closure.

• Mixed Species Plantings

  • Enhance structural complexity for wildlife habitats.
  • Can involve tree and shrub mixtures.
  • Useful for erosion control when shrubs are included.

• Strip Plantings

  • Effective on steep slopes.
  • Strips (20–50 meters wide) planted along contours with unplanted gaps between.
  • Gaps may be colonized by seedlings from planted areas.

• Direct Seeding

  • Useful when seeds are plentiful, viable, and have good germination rates.
  • Requires roughened or lightly buried soils to prevent washout or wind dispersal.
  • May not be effective in soils lacking mycorrhiza.

Priority Areas for Planting in the First Few Years

• Nature Reserves

  • Focus on areas adjacent to small patches of undisturbed forest.
  • Prioritize sites with endangered or rare wildlife populations.
  • Establish corridors connecting residual forest patches.

• Undesignated Areas

  • Prioritize bare areas along rivers and streams (at least 20 meters wide).
  • Focus on eroding slopes with deep-rooted species.
  • Consider areas adjacent to human populations that can supply timber.

Protection of Restored Sites

• Young sites require protection from grazing, fire, and human activities like fuelwood collection.
• Fencing may be necessary for certain sites to prevent disturbance.

Monitoring and Adaptive Management

• Monitoring is essential to assess the success of reforestation.

• It should be explicitly linked to the restoration objectives of each site.

• Monitoring questions may include:

  • Weed competition
  • Seedling survival and health
  • Tree density and species diversity
  • Regeneration of each species
  • Wildlife use of the area
  • Evidence of soil erosion

• Monitoring can start with a simple photo point system (same camera, same direction, regular intervals) and progress to more detailed methods as needed.

Early Management Tasks

• Identify actions that can be carried out in 2008 and those that must wait until 2009.
• Determine responsible bodies for nature reserve and undesignated area restoration.
• Clarify available funds and resources (e.g., fertilizers, labor).
• Plan the timing and quantities of seedlings to be raised for 2009.
• Identify local experts for plant biology and wildlife habitat advice.
• Review the need for reforestation in shallow soil areas (<100 cm) to improve slope stability.

Decision Tree for Deep Soil Sites (>100 cm)

1. Is the site within a nature reserve?
   • Yes
     • Is intact forest nearby?
       • Yes: Establish buffer areas or corridors.
       • No: Ignore for now.
   • No
     • Is it close to a river or stream?
       • Yes: Reforest strip along river.
       • No: Is it close to a road?
         • Yes: Establish plantation with commercially useful species.
         • No: Need to replant to stabilize slope?
           • Yes: Plant with deep-rooted species (in strips?).
           • No: Ignore for now.

The World Bank and GFDRR

• The working paper is produced by the East Asia and Pacific Disaster Risk Management Team of the World Bank, with support from GFDRR.
• It is part of a series of good practice notes on post-disaster recovery following the Wenchuan Earthquake.
• Content was coordinated by the China and Mongolia Sustainable Development and Country Management Units of the World Bank.
• The document highlights sector-specific lessons from global post-earthquake recovery programs.