Forest Investment Account (FIA) - Forest Science Program
FIA Project Y081147

    Structural recovery in second-growth forests on Lyell Island, Haida Gwaii
Project lead: Pearson, Audrey (University of British Columbia)
Author: Pearson, Audrey F.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
The purpose of this project is to provide baseline data on second-growth structural and compositional recovery for both tree and understorey species (defined as ecosystem recovery) in riparian and upland forests. We have do not have a good understanding of the habitat potential of second-growth forests, including riparian forests, or baseline data for determining targets for restoring structural complexity and compositional diversity associated with the original old-growth forests in second-growth forests. Many of our riparian areas in coastal BC are second-growth because those forests had the most accessible, highest volumes of timber and were logged first. However, these are also the most productive forest sites so the greatest potential for ecosystem recovery, especially since they are often our oldest second-growth.
The Millennium Ecosystem Assessment, an analysis of the state of the world’s ecosystems, concluded there were virtually no baseline historical data - essential for accurately assessing conditions and trends in biodiversity. In order to determine the effectiveness of stand-level attributes for maintaining biodiversity, we need such baseline information on stand-level attributes to develop targets and management guidelines. Lyell Island (Gwaii Haanas National Park Reserve) is an ideal location for such an investigation. There is a range of seral stages (both logging dates and methods), the area will never be logged again (so can provide a long term baseline) and is being managed solely for biodiversity values. Further, many historical data sources have already been compiled. The original forest composition and riparian zone (based on terrain units) have already been reconstructed from historical sources (1937 air photos and 1966 forest cover maps) (Pearson and Gergel 2006), so a landscape-level environmental baseline already exists to which the second growth information can be linked. There are also 1966 cruise data and ecosystem plot data from the 1970s/1980s to further verify the characteristics of the original old-growth stand, including understorey species. In addition, there are old-growth structure and composition plots and gap transects from a previous wind disturbance study that can serve as a comparative baseline (Pearson et al. 2005) and second-growth growth and yield plots that were established in 1962. Finally, a stream restoration project is already underway with Haida Fisheries, Parks Canada and other agencies where the riparian forest information can be directly applied.
Based on the air photo record, logged areas will be delineated into three classes: early logging (pre-1937), logging 1937 – 1970, logging 1971 – 1987, stratified into riparian and upland areas. Actual data of logging will determined from second-growth tree ages in the field. Second-growth forest structure and composition will be determined from forest structure plots and gap transects following standard techniques (See experimental design and methods.) The characteristics of the original stand will be determined from the original forest composition derived from the 1937 air photos and 1966 forest cover maps, abundance and species composition of stumps and logs remaining on the ground, air photo interpretation and historical data sources (such as old-growth plot data). The accuracy of the reconstruction will be tested against old-growth information for Windy Bay, which was never logged, so can serve as test of differences between old-growth attributes on the 1937 photos and modern photos/field verification. We will focus our analyses on differences in forest structure and composition with different eras of logging. Did western redcedar successfully regenerate on pre-1937 logged areas before introduced deer were abundant? Are residual Vaccinium and other shrub species more abundant in early logging sites? What is the dead wood legacy (sizes, species, decay classes of logs and snags) in second-growth forests? Do sites that were A-frame logged have more residual structure than modern clearcuts (e.g. Deal and Tappenier 2002)? To what extent can second growth provide habitat values (using forest structure variables as a surrogate for habitat)? How do those habitat values change over time (using logging date as a time variable)? How can we best accelerate structural and compositional recovery in second-growth forests, especially riparian forests?
This project will contribute to an ongoing research effort on ecosystem recovery in second-growth coastal forests of both field investigations and modelling. This project will link with a riparian restoration project in Kennedy Flats (Clayoquot Sound) as well as simulation modelling of forest succession under different management scenarios, including restoration (LLEMS). E.g. How does structural and compositional recovery (especially of understorey species) in Haida Gwaii compare with that of other second-growth coastal forests where introduced deer are not a factor, such as the Kennedy Flats and the Mid-Coast? This project will also contribute data to an ongoing study of conversion of old-growth cedar to second-growth spruce/hemlock forests from introduced deer. All these projects will contribute to a broader understanding of second-growth recovery, including recovery of habitat values and development of the best techniques for restoring structural complexity and compositional diversity in second-growth forests in order to maintain biodiversity.
The key forest management issue addressed by this project is forest structural and compositional recovery following logging, in both upland and riparian forests. There are several potential values of this project to the Haida Nation. There is great concern about future sources of western redcedar for cultural use given current rates of logging and lack of cedar regeneration from overbrowsing by introduced deer. If cedar did successfully regenerate on early logging sites when deer were far less abundant, these sites may be future sources of cedar for cultural use. Further, recovery of understorey species of cultural value is also of concern, especially with introduced deer. Second-growth forests are generally depauperate in understorey plants from crown closure but when canopy is opened, understorey species increase, which may occur in other areas, but not in Haida Gwaii due to deer. Information on structural recovery of second-growth riparian forests will be valuable for salmon habitat restoration (e.g. future sources of large woody debris in streams). Salmon habitat is extremely important to the Haida Nation. Finally, this project will provide training opportunities in forest research for the Haida Nation through Haida Heritage and Forest Guardians. Building professional capacity within their Nation is also an important priority.
Related projects:  FSP_Y092147
Contact: Pearson, Audrey, (604) 732-1256,


Executive Summary (27Kb)

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Updated August 16, 2010 

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