Thank-you for seeking clarification regarding the confusing wording of my entry. A. circinatum is indeed native to Seattle, generally. Specifically, in the second-growth forest where we live near sea level, I understand that A. circinatum is not native; alas, neither is Abies grandis. Perhaps they were before the area was logged off near the turn of the 19th into the 20th century, but that seems unlikely. On a major portion of the property, indeed of the island where we live, the dominant plant association is Pseudotsuga menziesii, Arbutus menziesii (which has allelopathic properties, I understand), Gautheria shallon, and Vaccinium ovatum. I understand that this indicates dry, nitrogen-poor, humus-lacking soil, which may not favor A. circinatum, which likes moist soil, although V. ovatum does prefer more moisture as well. There are areas where Thuja plicata, Salix scouleriana, Tsuga heterophylla, Alnus rubra, and Cornus nuttallii grow as well, which indicates a bit more moist soil. Moving into the ravine where A. macrophyllum, which is the first to populate any clearing with prolific seeding, and Thuja plicata are healthy and grow to great size, one still does not find A. circinatum or Abies grandis. If I remember correctly, I heard at a local lecture years ago that this is true for most of the island. Thus this species is in our collection, and does require additional watering, but is not native to our native woods.
Sure, distributions are uneven within the range. Vine maples can also be scarce in Island County. However, if you are talking about the island I think you are talking about a possibly spontaneous example of vine maple with a trunk 4'6" around was measured across from 10801 Bank Rd in 1992. See Champion Trees of Washington State, page 15. Puget Sound bluffs are capped by groves of grand firs, particularly noticeable from out on the water. UBC Lam Asian Garden & vicinity also has a stand. Site analysis handbook Indicator Plants of Coastal British Columbia (UBC Press, 1989) may be of some interest to you. It gives the Distribution and Ecological Characteristics of vine maple as "A shade-tolerant to shade-intolerant, submontane to montane, Pacific North American deciduous shrub (rare on Vancouver Island). Occurs in maritime to submaritime cool mesothermal climates on fresh to very moist, nitrogen-rich soils; its occurrence decreases with increasing elevation and continentality. Plentiful and persistent in open-canopy forests and clearings on water-receiving (alluvial, seepage, and stream-edge) sites; dominant in primary successional stages on water-shedding sites with fragmented colluvial soils. Regenerates vigorously from stump sprouts; it hinders natural regeneration and growth of shade-intolerant conifers. Frequently grows with Polystichum munitum. Characteristic of Moder and Mull humus forms."
There was an interesting discussion (started by me) about theories why Acer circinatum is almost non-existent on Vancouver Island. Acer circinatum not on Vancouver Island?
pretty sure they just werent strong enough growers to succesfully make it to vancouver island. not enough seed production?
