Native conifer forests of New Zealand

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Native conifer forests of New Zealand

• Dr. Kim Brown
• Dept. of Env. Plant Biology
• NZ seminar, Fall 2005

Unless otherwise noted, all images from Dawson
Lucas 2000, Nature guide to the New Zealand Forest
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80 of all tree species in New Zealand are
ENDEMIC
Dawson Lucas, 2005
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Questions

• Where do we find native conifer forest in NZ?
• How have humans impacted conifer biogeography?
• How long have conifers been in NZ?
• What features of NZ conifers that are unique, or
  similar to conifers in eastern US?
• What is a phylloclade? leaf dimorphism?
• What is a podocarp?

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CLIMATE CONTEXT
Note Precipitation gradient Isotherms of
temperature
Wardle, NZ J. Bot. 1964
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On a landscape scale, microclimate dictates the
range of species (lt- note treeline in forest
pic)
Dawson Lucas, 2005
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Where do we find native conifer forest in NZ?

• Conifer (podocarp)/broadleaf forest most
  widespread
• Mainly in lower elevation areas
• Current distribution greatly reduced due to human
  activity

Source AgriQuality and MAF        
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Ecosat forests
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How have humans impacted conifer biogeography?

• Clearing for
• Settlement
• Food production
• Timber resources
• Planting
• Natives
• Non-native

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Fleet (1984) New Zealands Forests
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Fleet (1984) New Zealands Forests
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Fleet (1984) New Zealands Forests
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Fleet (1984) New Zealands Forests
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Fleet (1984) New Zealands Forests
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How long have conifers been in NZ?

• 100 million years ago!
• noted in the fossil record prior to Gondwanan
  breakup

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What is a podocarp?

• Botanical family Podocarpaceae
• 7 genera (mostly S. hemisphere)
• 3 genera well represented in NZ
• Podocarpus
• Dacrydium
• Phyllocladus

Pouakani, the largest known Totara and largest
tree in the Podocarpaceae C.J. Earle,
10-Mar-2003.
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What is a phylloclade?
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What is leaf dimorphism?

• Juvenile leaves are morphologically VERY distinct
  from mature forms
• Thought to be a physiological (or even herbivory)
  strategy

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Lancewood 3 species in this genera lt-
(Pseudopanax crassifolius) Juvenile versus
mature forms
Dawson Lucas, 2005
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What features of NZ conifers that are unique, or
similar to conifers in eastern US?

• Needle, scale like leaves
• Make cones
• Wind pollinated

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What features of NZ conifers that are unique, or
similar to conifers in eastern US?

• Many rely on birds for seed dispersal with fleshy
  fruits
• (here, Taxus and Juniperus do)

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Questions

• Where do we find native conifer forest in NZ?
• How have humans impacted conifer biogeography?
• How long have conifers been in NZ?
• What features of NZ conifers that are unique, or
  similar to conifers in eastern US?
• What is a phylloclade? leaf dimorphism?
• What is a podocarp?

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Leaf area distribution and canopy clumping in an
old-growth mixed species podocarp NZ rainforest
Kim J. Brown1, W. Schuster2, D. Whitehead3, D.
Tissue4, M. Turnbull5 and K.L. Griffin1
1Lamont-Doherty Earth Observatory, Columbia
University NY 2The Black Rock Forest, Cornwall NY
3New Zealand Landcare Trust, Lincoln NZ 4Texas
Tech University, Lubbock TX 5University of
Canterbury, Christchurch NZ
Research supported by Andrew W. Mellon
Foundation CERC, Columbia University Timberlands
NZ
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Research site Okarito Lagoon, New Zealand
Slow growing, mixed-podocarp forest, 600
years old Highly leached organic soils over
glacial gravels Annual rainfall 3 m, limited
sun, moderate temperatures Little
ecophysiological previous research on NZ
podocarps
South Island, NZ
Okarito Lagoon
Stewart Is.
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Research Objectives
Specific Objectives of this research Estimate
Leaf Area Index (LAI) with non-destructive
methods - partition into overstory and
sub-canopy components Describe the 2-D
distribution of leaf area in research plot
Determine canopy clumping correction factor to
adjust LAI
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Optically- determined LAI is often lt harvested
LAI
canopy clumping factors have been used to
reconcile the two
Heterogeneous, cylindrical tree canopies
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Methods - Field LAI measurements
Li-Cor LAI-2000, abovebelow canopy
Gimbal self-leveling mount
Sampled every 5m on 50x50m grid
Measures taken _at_ 1.5 and 7 m
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Dacrydium cupressinum (rimu) shoots are clumped
Clumping correction factors for LAI2000 after
Gower and Norman (1991) Cp ap / Ap
(0,0) where ap max. projected area of all
needles Ap shoot projected area with
camera perpendicular to
horizontal shoot (If Cp 1 then all needles
displayed equally)
Cp LAI2000 corrected LAI
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Methods - Clumping correction factors for rimu
Fassnacht et al. (1994)
Cp ap / Ap
Four shoots from top, middle, bottom of 3
trees Projected areas for each photographed at
5 camera angles (0, 15, 30, 45,
60) 8 shoot angles
(0, 30, 60, 90, 180, 210, 240, 270) Metal
sphere used with each shoot for scale Adobe
Photoshop NIH Image used for analyses
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Okarito Forest - Stand Characteristics
rimu
rimu
Stand visualization from 50x50m plot
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Spatial variability of LAI Measures at Okarito
LAI 2.87 .04 s.e.
(Understory contributes 0.4)
Map of LAI values at Okarito 50x50 m plot
Circle size a LAI value, red tower
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Rimu shoot morphology compressed with increased
canopy height
Lower
Upper
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Conclusions
Rimu was the dominant species at Okarito LAI
values extremely low (2.87 0.04)
(understory contributes small amount, 0.4)
Rimu shoots highly clumped, (clumping varied
strongly with canopy position) LAI-2000
determinations of LAI were fairly homogeneous
. . . Clumping factor ----gt ?