Pseudotsuga menziesii
Environmental Weed (2024)
Common names
Douglas fir, Oregon pine
Biostatus
Exotic
Category
Vascular
Structural class
Trees & Shrubs - Gymnosperms
Flower colours
No flowers
Detailed description
Very large resinous evergreen tree. Bark thick, reddish-brown beneath, rough and furrowed when mature. Branches in irregular whorls, horizontal; branchlets usually drooping. Shoots light to dark brown, ridged, with short hairs. Winter buds to 1 cm long, shining purplish-brown, narrow and sharp. Leaves 15–38 × 1–2 mm, in 2 ranks, needle-like, whitish beneath, edges often rolled, orange-scented when crushed. Male cones 12–20 mm long, catkin-like. Female cones 5–10 cm long, cylindric, papery, downward-pointing; seed scales large and broad; bract scales longer and thinner than seed scales, 3-pointed, centre point longest.
Similar taxa
Pseudotsuga can be separated from Tsuga as it lacks the persistent leaf base. Pseudotsuga macrocarpa is known to be cultivated in New Zealand and has cones 10–18 cm long. Pseudotsuga sinensis and P. japonica are also cultivated in specialist collections; both are from Asia.
Habitat
Terrestrial. A plant of lowland, montane and subalpine habitats growing in sites with low-moderate fertility (Timmins & MacKenzie 1995). A plant of scrub and forest margin communities, shrublands, tussockland and light wells in forest (Timmins & MacKenzie 1995).
Conservation status
Not applicable
Detailed taxonomy
Genus
Family
Ecology
Year naturalised
1925
Origin
N. America
Reason for introduction
Forestry.
Tolerances
The plant is tolerant to shade, more so than other conifers and intolerant of drought. The plant is frost tolerant when it is higher than 2 m. Physical damage results in regrowth if green foliage remains intact, recovers from browsing (Timmins & MacKenzie 1995). The plant recovers after fire if there is an adjacent seed source.
Life cycle and dispersal
Perennial. Seedlings require the presence of a mycorrhizal fungi with seedlings establishing most readily on well lit sheltered sites where there is no competition from other vegetation. The plant seldom spreads onto land where vegetation cover is dense. Seed is produced at a rate of 20,000 seeds per mature tree annually (Timmins & MacKenzie 1995).
Seed is dispersed in autumn and winter by wind and gravity and remains viable for a few weeks to many years.
Propagation technique
Seed
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs in uplands (non-wetlands).
Other information
Extra information
The National Wilding Conifer Control Programme team at Biosecurity New Zealand, a branch of Ministry for Primary Industries, has produced this wilding conifer quick ID guide.
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
PSEMEN
Referencing and citations
References and further reading
Timmins SM, Mackenzie IW. 1995. Weeds in New Zealand Protected Natural Areas database. Department of Conservation Technical Series 8. Department of Conservation, Wellington, NZ. 282 p.