Puget Sound Native Tree
Botanical Garden
Puget Sound Successional Forests
Although the regional Puget Sound climate is cool summers and moderate winters, the rainfall is very limited from May though October, often only receiving 1-2" in that period. Hurricane strength winter winds, colossal infrequent summer forest fires, and landslides generated by rainwater and periodic earth quakes sometimes destroy hundreds, if not thousands of acres of forest.
The climax communities created by ancient forests rebuild themselves by species evolved to thrive in the newly opened sunlit and dryer lands, grasses and local brush. Within five years Alder, Maple, and Cottonwood shove up through the first responders and within 20-50 years create a swath of competing trees that cool and moderate soil temperatures.
Continued at bottom of page
Western Hemlocks eventually succeed the Douglas Firs, their seedlings can survive in a lower light level. The roots of the Hemlocks can tolerate the slight acidic pH of the moss the seedling grow in, especially on downed timber, creating cathedrals and nurse logs.
Western Hemlocks are easily identified by the "drooping" tips of the upper branches and top.
Douglas Firs where the small 12" daimeter "post" is still alive and supported by the root system of the larger tree. This symbiosis assistance is describe in the "Hidden Life of Trees".
In 1870 when the property was first logged, the smaller "post" was likely larger than the now larger tree and cut for firewood. It continues to survive in a communal state. This forest 'speaks' to those who will listen about how to survive 500 years.
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Fire Weed - First Responders
Fire Weed
Red Alder Leaves : 4-6" across
Red Alder Bark
24 hours after an injury, the exposed bark becomes bright orange/RED. Fades to gray brown after 2-6 weeks.
Red Alder roots have nodules that contain bacteria capable of chemically combining atmospheric nitrogen, N2, into organic nitrogen, a required chemical necessary for forest health. The fact that alders show first and fastest then revitalizes the forest soil. Forests that recover after the succession of the alders are healthier.
The trees grow so fast that the bark splits and heals, leaving long vertical furrows and scars.
All pictures taken at the Botanical Garden except where noted
Big Leaf Maples are the largest maples in the world, up to five feet in diameter and leaves larger than 12 inches across. The bark is typically groves and support communities of moss, lichen, and ferns and raccoons mark their territories by shatting in upper boles and on large horizontal branches. These depositories are in continuous use for years and decades and are fun to find while climbing.
Douglas Firs can grow under the filtered sunlight of the alders and maples, and continue to grow in the wintertime when the others shed their leaves. This slow growth eventually leads to the Doug Firs over topping the deciduous tree. The growth of the firs speeds up at this point growing toward the 200-300 heights they are capable of. The alders struggle much more than the maples to get sunlight, and towards the end send out multiple attempts at creating new branches (suckers) along the trunk before they die.
By 100 years Douglas and Grand fir begin topping the alders by growing even in the fall and winter, and start killing their predecessor deciduous trees by blocking the sun.
The next succession is the events caused by the 400 year Douglas fir forest, their own shade creates a moist understory, too dark for their own germinating seeds to survive. However, Western Hemlocks can survive and very slowly grow in that environment. In addition, moss can grow in the moist environment and will change the pH of the soils such that it becomes difficult for tree roots to successfully process their cell boundary osmosis requirements, this thinning the trees that block their sun and light needs. Hemlocks are more successful in growing in moss covered logs and soils, and since the logs are elevated 2-10 feet above the surrounding landscape, Hemlocks have an advantage over Doug firs, and eventually take over the forest, at least until the next catastrophe.
Most of the region is hilly or slopes, but where flat land creates standing water, the weak acidic pH created by moss will eventually kill the trees and a bog or glenn will be the result.
Picture of 2' diameter Red Alder
Succession: Fireweed becomes > Alder > Doug Fir > Hemlock > Moss..
Note: Our largest Broadleaf tree, the Black Cottonwood, thrives on shifting sands and soils surrounding rivers. These rivers provide strong sunlight and moisture, and often sweepaway the toowering conifers.