Biometric Challenges of Hawaii Forest Management

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Biometric Challenges of Hawaii Forest Management

• N. Koch
• Research Forester

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Introduction

• Current problem
• Lack of adequate data and models for proper
  native forest management
• History
• How did this come about?
• Present situation
• Why such models are more important today?
• Currently used methods for forest management
• Mostly empirical

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Focus on koa

• External volume equations for most exotic
  species are well known
• Allows for adequate management, with reservations
• No site indexes
• No stocking guides
• No growth curves (yet)
• However, better than the situation for koa!

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Background

• Historic lack of dedicated forest industry in
  Hawaii
• Most forest cleared for other uses
• Grazing
• Agriculture
• Sugar
• Pineapple
• Remaining forests dedicated to non-timber use
• Watershed protection
• Parkland

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Background (cont.)

• Forest industry relegated to mining of timber
  resources
• Clearing land for agriculture
• Extraction of pasture timber
• Small-scale extraction in watershed forests

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Existing models

• Early efforts by the Forest Service
• 1960s and 1970s
• Predicting volumes in four Hawaii
  hardwoods...first multivariate equations
  developed Sharpnack, David (1966)
• ...requires 4 inputs
• DBH
• HT
• TDIB (top diam. inside bark)
• Diam. Inside bark at 1st 16 log

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Existing models (cont.)

• Acacia koa volume (cuft)
• V -13.8719 1.7332 (DBH) 1.2125 TDIB
• 0.0022 DBH2 (HT) (FC) 0.0033 TDIB2 (HT) (FC)
• 11.7450 (HT)
• TDIB Top inside bark diameter
• FC - Form class Inside bark diameter at 16 /
  DBH
• ...Laborious to collect data and process it!!!

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Existing models (cont.)

• Early efforts by the Forest Service
• 1960s and 1970s
• Guide to log defect indicators in Koa, Ohia...
  preliminary rules for volume deductions Burgan
  et al. (1971)
• ... Difficult to apply in field estimations

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Present situation

• Demand for quality forest products outstrips
  supply, particularly in native woods
• Increased conversion of pastures to forest
• Increased interest in active forest management
• A shift from extractive uses
• Forest management in Hawaii as a worthwhile
  alternative to agriculture/grazing
• Environmental concerns
• Government incentives
• Wood prices (koa is worth more than mahogany)

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Present situation (cont.)

• Forest management for timber based on rudimentary
  equations
• Eg. Use of Acacia melanoxylon in lieu of A. koa
• Difficult to establish value of standing trees
• Little data on site indexes, growth curves,
  stocking guides
• Unknown returns on forest investment
• Difficult to prepare silvicultural prescriptions

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Present situation (cont.)

• Use non-volume basis for native forest management
• Basal area
• Stems/acre
• Diameter distribution
• Not able to utilize volume control for allowable
  harvests

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Complicating factors

• Acacia koa
• Variable growth form
• Young forest

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Young, forest grown Koa
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Young, forest grown Koa
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Complicating factors

• Acacia koa
• Variable growth form
• Young forest
• Pasture forest relicts

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Forest relicts
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Forest relicts
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Forest relicts
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Complicating factors

• Acacia koa
• Variable growth form
• Young forest
• Pasture forest relicts
• Old field

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Old field Koa
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Old field Koa
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Complicating factors

• Acacia koa
• Variable phenotype
• Young forest
• Pasture forest relicts
• Young pasture
• Genetic variability
• Heartwood (important value driver)
• Elevational
• Inter-island

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Genetic variability of heartwood
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Current work

• Exotics
• Division of forestry and wildlife has prepared
  local volume equations for
• Eucalyptus grandis
• Eucalyptus saligna
• Flindersia brayleyana
• Forest solutions working on young koa volume
  equations (DBH HT based)
• Taper data collected

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Current challenges

• Coordination of data collection and synthesis
• Preparation of local volume equations, growth
  models and stocking guides
• Partnerships with land management agencies
• Collaboration with biometry experts
• Invitation
• Forest Solutions would like to collaborate with
  biometry experts to resolve these issues