British Columbia: Tree Diversity

Discussion in 'Pacific Northwest Native Plants' started by Chris Morris, Mar 5, 2016.

  1. Chris Morris

    Chris Morris Active Member 10 Years

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    I recently noticed while walking on Burnaby Mountain that certain trees are very abundant and some are almost non existent, for instance I saw lots of western red cedar, western hemlock and big leaf maple, but only one douglas fir, one Sitka spruce and two tiny pacific yew.

    I realize why certain types of trees dominate and others don't, shade tolerance, full sun requirement etc. but does anyone see this as a problem, not specifically on Burnaby Mountain but in southern B.C as a whole, and if so, is anything being done about it, for example, are cities, restoration groups, native plant growers focusing on less dominant trees to support more diversity or when people buy native plants for restoration sites, do they just get whatever happens to be available.

    I'm wondering if anyone else has an opinion about this.
     
  2. vitog

    vitog Contributor 10 Years

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    The trees that are most abundant on Burnaby Mountain are the ones that are best adapted for that environment. Western Red Cedar and Western Hemlock seedlings tolerate shade far better than Douglas-Fir seedlings, and the plentiful rainfall that this area receives promotes the growth of ample underbrush that prevents Douglas-Firs from getting a start. Natural forests in this area are dominated by the former two species, unless fires have opened up some space for Douglas-Fir seedlings.

    Around Burnaby Mountain (and other parks in the area) I've noticed that the underbrush is often so thick that large areas have only scattered large trees and practically no young dominant (upper story) trees. This under story vegetation seems rather monotonous compared to natural old-growth forests where the under story is less dense but appears to be more diverse. I don't think that planting less common species as part of small scale restoration efforts will have any significant impact on the situation. What would be more beneficial to diversity are controlled burns to clear out some of the areas of heavy underbrush. This would allow natural regeneration of diverse species on a far larger scale. However, I can't see that happening in this urban setting; so we are stuck with ever expanding areas of salmonberry bushes and invasive blackberry vines.
     
  3. Georgia Strait

    Georgia Strait Generous Contributor 10 Years

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    re: Blackberry vines ---- for me, it's normal to see the invasive and very big mounds of large-leaf, large-berry Himalayan plant these days either along commuter rail lines in the Valley or off the side of bulldozed roads, etc - and I know they are a menace tho birds sure like the berries.

    http://bcinvasives.ca/invasive-spec...species/invasive-plants/himalayan-blackberry/

    What I don't see so often any longer (tho very common as kids in the 60's around the greater Vancouver rural areas) is the smaller blackberry vine with reddish color, very defined leaves smaller than the common one today, and smaller berries. I don't know latin name. I know it's not bramble (below). What were those plants - and were they introduced invasives or natives?

    are salmon berries native in BC? Salmonberry | LFS Indigenous Research Partnerships

    in addition, there are the very low-growing 'brambles' that we've all tripped over and scraped our ankles ----- I think this is the latin name (below) - and they are native.
    Rubus ursinus (trailing blackberry)

    re: the Original Poster's question - I am not a biologist - however, my "arm chair" opinion about the groups that are keen on re-planting and so forth wild land is have an overall plan guided by professionals who are on side ..... then 1. (step one) - remove safely and dispose properly any invasives ---- then plant if need be (ie the natural plants can't just grow in). I'd say that these efforts should be taking in to account the fauna too. For example, dead trees might appear "ugly" to our design ideas - however, are precious to many birds and insects and other animals. I would think - from my own small experience - that this is not a one-time effort - it has to be revisited and maintained for several seasons to ensure that the native rehabilitation takes hold.

    I would also hope that the nursery garden industry in BC would adhere to a code of standards that stops the introduction of future invasives ----

    and - my experience at the Coast and in the Okanagan is that human interference (eg bulldozing - atv/ing - overgrazing) often results in creating the ideal environment for invasives to take over, and that some have hopped out of the ornamental garden and taken over nature - often where a lazy gardener has dumped their trimmings etc on the side of a rural road or on to the beach or up the mountain power line road etc.

    I also realize that some weeds come in hay bales etc (hence the rule at some parks - you have to buy the hay for your backcountry riding and pack horses at the park - like this one in a secluded Cariboo Chilcotin valley
    Churn Creek Protected Area - BC Parks
    )

    ps - edit to add - I know there's a thread from 2015 in the "gardening Pac NW" forum about weeds that come with purchased top soil. I've had that - as did the person who started the thread - and that is a nightmare. I was inexperienced and in a hurry and bought what I thought was a truckload (not packaged) of good soil after a massive septic system rebuild. Ouch.
     
  4. vitog

    vitog Contributor 10 Years

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  5. Georgia Strait

    Georgia Strait Generous Contributor 10 Years

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    yes, thank you - I think what I recall on side roads rural areas back in the 60's is the first plant you list above.

    i know it's not what we now call Thimbleberry - that is more of a cane plant like raspberry or such.

    it seems to me that this blackberry was more common before the now common Himalayan

    how did either of them get here in SW BC?
    is there a guilty party hiding in the yellow broom? amongst the starlings?
     

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