Home | Login
 




Search Treegrower articles:

Join NZFFA

 


You are here: Tree Grower Articles > Tree Grower 2007, August >>

Douglas fir – Grows well and reproduces well



Nick Ledgard
New Zealand Tree Grower August 2007


Douglas fir cone litter under 20-year old trees in the Mackenzie Basin
Over the last decade, southern New Zealand has seen more new land planting of Douglas fir than any other tree species – including radiata pine. The reason is because it grows well in the inland parts of the South Island high country where world record growth rates have been measured. In such areas, Douglas fir not only performs well, but it reproduces well. Many readers will have seen the ankle-deep carpets of cones beneath trees, which can produce thousands of viable seeds almost annually. The seed is winged and light, and if produced in an exposed site can be distributed by the wind for many kilometres.

Vigorous spread

The above reasons contribute to the fact that Douglas fir is now recognised as a species capable of vigorous wilding spread. Surprisingly, this was not the case 20 years ago. It is suspected that the Douglas fir cone litter under 20-year old trees in the Mackenzie Basin increasing numbers of fast-growing wildings seen today are associated with the presence of mycorrhiza, symbiotic fungi associated with their root systems, which appear to have only become widespread
comparatively recently.


Behind Queenstown Douglas fir has moved a considerable way up the slopes of Bowen Peak in between 1986 and 2003


Douglas fir can establish under forest gaps

Shade tolerant

Douglas fir is more shade tolerant than the common pines and will invade shrublands. Small seedlings can also be found within forests, but contrary to popular belief, they will not establish readily under high canopies. Research has determined that the species needs 40% of full light to achieve the consistent growth needed to reach canopy level.

Cooler inland hills

The best growth for Douglas fir is often found in cooler, inland hill and high country areas, where the surrounding vegetation cover and grazing levels can be light. Such circumstances can lead to a high risk of wilding spread. Assessment forms are available to assess this risk, available from the author, and there are a number of strategies which can prevent or reduce it.

Grazing and improved pastures are the most obvious – one never sees a wilding alongside the many-species shelterbelts growing on developed farms. Fertilising alone will increase competition from resident vegetation and thereby reduce wilding emergence. But the increased fertility may also promote exotic weeds which can submerge slower growing native species. Another option is not to plant on exposed take-off sites, or to plant a less spread-prone species, such as ponderosa and radiata pine, around stand margins as much of the seed leading to wildings comes from edge trees. However sometimes, despite there being excellent growth opportunities, the risk of spread can be just so great that Douglas fir should not be planted at all.

Douglas fir research co-operative

The author is secretary of the New Zealand Douglas fir research co-operative, and also currently manages a three year wilding project funded by MAF’s Sustainable Farming Fund. It involves all the major stakeholders, and aims to make wilding prevention and control an accepted component of everyday farm management.

Nick Ledgard works for Ensis in Christchurch


Douglas fir can also invade shrublands

(top)



    Farm Forestry
    - Headlines

  • Global call finds NZ forest policies wanting
    March, 2015
    Forest owners and wood processors world-wide are calling for governments to recognise the role of forests and wood products in combating climate change. Forests and climate change is the theme…

  • Forest safety council underway
    February, 2015
    The forest industry has established a safety council to make forests safer places to work. This was a key recommendation of the Independent Forestry Safety Review Panel that reviewed forest…

  • Trees, soil and you
    February, 2015
    A new survey has been released by Scion to capture current industry opinion regarding the value of soil data to forest managers, as part of the Growing Confidence in Forestry’s…

  • Scion scientist helps control recent Marlborough fire
    February, 2015
    Modelling systems developed by Scion were used during the recent Onamalutu forest fire to effectively and safely manage fire fighting efforts. Wildfires are a significant risk to New Zealand forests.…

  • Don’t go down to the woods today
    February, 2015
    With the risk of forest fire now very high or extreme in many parts of the country, the public is being cautioned not to enter plantation forests without permission. FOREST…

  • ETS Crisis Meeting called for
    February, 2015
    Forest owners are asking the government to call an urgent meeting of primary sector leaders and iwi to deal with the country’s greenhouse gas emissions blow-out. They say a lack…

  • Diverse Forests, Emerging Opportunities
    January, 2015
    Issue 2, January 2015 A new future for diverse forests research Welcome to the second edition of our quarterly newsletter. In the first issue (September 2014), we highlighted our recent…

  • NZ FORESTS GAIN INTERNATIONAL VISIBILITY
    January, 2015
    With the acceptance of the NZ Forest Certification Association (NZFCA) as New Zealand’s PEFC Member, New Zealand forest growers gain visibility in the world’s leading forest certification system.  “We are…

  • Trees on Farms SFF project winds up
    January, 2015
    The Trees on Farms Workshops Project, a major MPI Sustainable Farming Fund project which was managed by the NZ Farm Forestry Association, is complete. NZFFA – Media Release, January 22nd…

  • Research at Scion: What do fire danger signs mean?
    January, 2015
    New research shows that the iconic fire danger signs may need to be updated to better promote fire safety across New Zealand. The familiar multi-coloured fire danger signs are a…

  • Growing Confidence in Forestry's Future (GCFF) Research Programme: Wind, snakes and forest production in South America
    January, 2015
    John Moore reports on a wind impact conference and provides his observations of intensive plantation management in South America. The effect of extreme wind events on plantation productivity is an…

  • New Work on Biological Control for Eucalyptus Tortoise Beetle
    January, 2015
    LATEST NEWS: Promising Biological Control agent imported into Containment On December 12th 2014, NZFFA representative on the SFF project team Dean Satchell brought back from Tasmania an exciting present: a…


  • article archive >>

Copyright © 1998-2015 www.NZFFA.org.nz All Rights Reserved | Site made using Radiant Content & Member Management System | Contact NZFFA