Dead Wood Is Good Wood

A large diameter fallen tree along Upper Goldstream Trail in Goldstream Provincial Park. Over hundreds of
years the fallen Western red cedar will provide nutrients for the large Douglas fir behind it.

In the Pacific rainforest dead standing and fallen trees may make up more biomass than the living giants towering above the soil. If it weren't for these dead trees, and the decomposers that break them down, the forest would cease to exist.


According to renowned forester Chris Maser, ‘decaying wood serves as a savings account of soil organic materials and nutrients in forest ecosystems’. This is one reason landowners should not try to "clean up" forested areas. They need to be messy in order to function properly.


Sometimes messy old growth forests are deemed "decadent" to justify cutting them down. But you can't improve on the natural cycles of life and death.

Fallen large trees enhance fish habitat by providing shade and structure.
These downed trees are over the upper Goldstream River.

Dead wood is also a boon to forest wildlife.

In the words of forest scientist Charles Elton, "dying and dead wood provides one of the two or three greatest resources for animal species in a natural forest...if fallen timber and slightly decayed trees are removed the whole system is gravely impoverished of perhaps more than one fifth of its wildlife component".

The healthiest forest is an untouched forest, in all its messy, "decadent" glory.

Wildlife Trees: A Wonderful, Rotten Place To Live

Detail of signage in Cypress Provincial Park describing the importance of wildlife trees

Giant Fallen Douglas-fir Snag

The huge Douglas-fir snag took out a branch of a Bigleaf maple on the way down

On a recent trip up Sooke River road to Sooke Potholes Park to view spawning salmon, I noticed this massive ancient Douglas-fir snag that recently succumbed to the relentless pull of gravity. It looks like it probably made a sound - a big sound.

I am surprised I didn't notice this massive remnant from the ancient forest of days gone by before it fell. It is just off the road, and it is huge! The Douglas-fir had already lost its top which was nowhere to be seen. The 20 meter wind-snapped snag remained, and stood until very recently.

This tree was probably hundreds of years old when the top came off. The remains could have stood for another hundred years or more. During that time insects moved in creating pathways for other organisms that slowly eat and break down the wood. Beetles, sow bugs, termites, centipedes and slugs all came to the banquet.

Soft, decaying wood in large snags allows cavity nesting birds, like woodpeckers, to dig out comfortable homes. A spotted owl may have used the broken top to settle down in and raise a family. A squirrel family may have moved in after the birds moved out. The snag was a vertical ecosystem unto itself, hosting literally billions of organisms.

Having fallen, the snag changes status. Now it is 'large diameter woody debris', an integral component of old growth coastal forests. It will add to the forest floor for hundreds of years more as it breaks down further, providing rich nutrients and habitat for many more organisms.

Perhaps a salamander will discover and occupy the log. Salamanders have smooth, unprotected skin, that requires a moist environment. They don't like heat or dryness, so the fallen log is a perfect haven.

Slabs of thick bark

Decaying logs are sponges that soak up enormous amounts of water over wet coastal winters. During summer droughts the log provides the moisture that the salamanders need.

The tree's status may yet change again, as the log decays into the forest floor and tree seeds establish themselves on it. Then it will be known as a 'nurse log'.

When this huge snag fell, echos of the past resounded through the forest. It was a reminder of the change that happens constantly in intact forest ecosystems.

It was also a reminder of how humans have interfered in this process. Trees like this one are rare today due to our misguided intervention.

Super-Sized Douglas-fir Snags Important Bird Habitat

One giant, old growth large diameter snag

Up the Sooke River in a not-so-secret location, lies one of the largest Douglas-fir snags I have seen, and is a tree I like to visit from time to time. A snag is a dead, standing tree, and the one above is a prime example of a large diameter, old growth snag.

This centuries old tree probably snapped in a windstorm - what is left could stay standing for another century or more. In that time it will provide habitat for a whole ecosystem of interacting organisms and food webs. Although the tree itself may be dead, the structure itself is rich with life.

Birds in the coastal forest depend on these Douglas-fir snags. Up to 34 different hole-nesting species of birds use Douglas-fir snags for roosting or nesting. Woodpeckers are especially dependent on snags as they use them for roosting, nesting, and for feeding. They eat the insects living in the dead wood.

A study conducted in the 1970s in the coastal Douglas-fir forest found that snags provide crucial habitat for hole-nesting birds:

"On the average, hole-nesting birds used Douglas-fir snags over 60 cm in dbh (diameter at breast height - 1.3 meters/4 ft above the ground) and over 15 m tall for foraging and nesting; these snags usually had broken tops, few or no branches, decayed sapwood and heartwood, and less than 100% bark cover. Snags of this size and type occurred primarily in forests over 110 years of age; consequently, use of snags by hole-nesting birds was concentrated in older forests (>110 years old).

Density and species diversity of hole-nesting birds increased with forest age. Density of hole-nesting birds was positively correlated with mean dbh of snags. Intensive management of Douglas-fir forests does not allow for the production or retention of large snags. A reduction in the number of large snags could reduce populations of hole-nesting birds."

No snags, no hole-nesting birds.

Major Moss In B.C.'s Coastal Forests

This giant Douglas-fir snag makes a perfect scaffold for the moss

Fluorescent green flashes catch my eye whenever I am out in the forest. It is not surprising as anything that doesn't move in the coastal forest gets covered in deep, luxurious moss. Actually, I can say that even things that roll grow moss in the rain forest - my vehicle is slowly turning green. If left long enough it would disappear entirely, as would I if I ever fell on a hike and couldn't get up.

Detail of tree above showing a Western hemlock seedling growing out of the moss

British Columbia possesses the richest diversity of mosses, or bryophytes, in Canada. The amazing diversity of this large group of special non-flowering green plants is due to the varied terrain  of the province, as well as historical developments that led to holdovers surviving from before the last ice age. B.C.'s huge collection of mosses is greater than the combined mosses of all of the U.S. west of the Rocky Mountains. That's major moss.

The moss on big trees can be several centimetres thick, and cover the bark completely

This time of year the mosses are hydrated and at their colourful best. Moss can hold a whopping 25 times its own weight in moisture. They are efficient sponges which can add tons of weight to the limbs of an old tree, making them more susceptible to wind damage.

Old Bigleaf maple branches grow a covering of moss and ferns

Mosses are a special kind of green plant because they are non-vascular, meaning they do not have xylem or phloem (tissues that transport water and nutrients) like trees and other vascular plants. The Bryophytes are sometimes referred to as "lower" plants because they evolved earlier in the history of green stuff on the planet.

Winter, when trees don't have leaves, is a good time to see the full extent of the moss

The mosses shown here are all epiphytes, meaning that they do not harm the trees they are growing on. The base of trees provide a scaffold for the moss, but the moss derives all its nutrients from the air and rain, not from the tree. Mosses do not have true roots, only root-like threads called rhizoids. In the summer, mosses can dry right out. They survive by lowering their metabolism until the rains come again to fluff up the green cushions.

Could it be Amblystegium serpens, or Creeping feather moss?

Sometimes moss seems like it is from a different planet. Mosses are a varied, wonderful, and ubiquitous part of the coastal forest. So many different types of moss growing in so many different shades of fluorescent green. Just remember to keep moving out here or you may find yourself turning green.

Resources

For a good introduction to B.C. mosses see:

Schofield, W. B. 1992. Some Common Mosses of British Columbia. Royal BC Museum Handbook. Queen's Printer, Victoria, BC. 394 pages. Illustrated.

Galloping Goose Big Trees - Coopers Cove to Roche Cove

The Coopers Cove/Saseenos area of Sooke is a thickly forested rural area with outstanding old growth trees spread throughout the hillsides and shoreline. Most are on private land, but can be seen from vantage points along Highway 14, side roads, and The Galloping Goose trail.



The trail offers many opportunities to view impressive trees as you travel with forest on one side and the ocean down below on the other. A scenic stretch from Coopers Cove to Roche Cove Park has enough old growth trees among younger forest to keep you searching for the next giant.






Evidence of ongoing forest cycles are shown by one particular tree along this stretch of trail. The bleached and twisted snag pictured here was hundreds of years old when it met its demise. How long it has been standing since then is hard to say. Snags sometimes remain standing for hundreds of years. They are key structures in a mature and healthy forest.















As time passes the sun, gravity, wind and decay take their toll. Over the years this Douglas fir has lost its upper trunk and all limbs except a huge main branch, itself as thick as a large trunk.










Other branches have tumbled to the shoreline below and lay in a grey wood-grained nest worthy of a large packrat.








This de-barked limb rests on the beach below showing a wrinkly pattern where the branch bends.



Many large old trees, links to the unmolested pre-European forest, can be seen from the Galloping Goose Trail. There is a place to park at the trail head at Coopers Cove just at the side of highway 14. At the other end, at Roche Cove Park, there is also parking available.

A short way up the G.G. trail from Roche Cove you will find Matheson Lake Park. Here you can hike through ancient forest that has been preserved. I will be visiting Matheson in the near future. Look for a post and photos on some of the choice trees in this patch of old forest.

Impressive Douglas Fir Snag

This is actually a huge, short snag that is broken off just up from the top of the photo. The massive bole lies down the slope to the right, and is now large diameter woody debris enriching the forest floor structure. This ancient Douglas fir probably experienced a catastrophic event during a winter storm. Perhaps it was diseased which would make it more susceptible to wind.

This impressive snag is in a very narrow strip of old forest that has been cleared on either side, which made it vulnerable to wind. Other large trees in this area are likely to blow down, too. The fire scars on the foot thick cork-like bark above my head are pretty impressive. The burns record at least one forest fire.

In the recent past the Sooke area was carpeted in trees this large and larger.

Large Old Snags Very Important To Wildlife

Snags, or standing dead trees, like the one near the center of the above photograph, provide food and shelter for a richness of life. Birds nest in snags, and small mammals make homes there as well. Moss and lichen will live on the bark, while fungus and insects soften the core of the tree. A large snag could stand for 150 years or more before it finally topples to the forest floor.



At right is a blow up of the above tree showing a large diameter hole near the top. Woodpeckers, like the Pileated woodpecker, excavate holes in snags for feeding and nesting. The woodpecker digs a new nest hole each year so in subsequent years other birds or mammals may move into old cavities.


Snags are so important to forest ecology that British Columbia has a program to tag and protect such trees as "Wildlife Trees". These valuable resources are marked with a yellow symbol which identifies and protects them.




Many forest creatures can only live in large, old trees, and snags can provide the height and structure they require. The Spotted owl is an example of a bird that requires old trees for nesting, often setting up in snags, living in the hollow of the broken top.





Bald eagles use large trees for perching and nesting, often having a second nest nearby in a companion big tree. Eagle nests can weigh up to 1000 pounds - you need a big tree to be able to hold such a massive structure of branches.






The threatened Marbled Murrelet also needs old growth trees.

"Throughout the murrelets’ North Pacific range, most occupied nests have been found in tall trees. They were simple cups in the moss on thick branches, 20 to 40 m above the ground. Only fairly old Douglas fir and Sitka spruce have branches thick enough for murrelet nests, although other trees may offer suitable platforms or cavities.

Trees with thick branches near the top usually occur in stands of old growth and mature forests that are rapidly being cut for timber. If it turns out that British Columbia’s murrelets are not concentrated in colonies and have no alternative nesting habitat, the need to protect sites for murrelet nests will be another reason to preserve more of British Columbia’s coastal old-growth forests. However, a great many areas still remain to be explored for nests." http://www.hww.ca/hww2.asp?id=55&cid=7

When we save large old trees, whether they are dead or alive, we are also saving a vast richness of life that depend on such trees. Each ancient tree is an ecosystem to itself, and we are just now realizing their true importance. The snag pictured at top enriches Francis/King Regional Park, Saanich B.C.

Another Grand Beach Stump

Another semi-permanent feature of Billing Spit is this large chunk of tree left over after logging sometime in the distant past. More than likely it was logged from somewhere in the Sooke river watershed, and eventually tumbled down into a winter raging river only to flow out into the harbour and land here. This giant is toward the end of Billings Spit just on the west facing beach.

As far as I know this log does not move with storms or tides. It has been here for at least as long as I have been here, but surely its tenancy is much longer than just 5 years. No doubt it will continue to live here for many years in the future.

Check out the DBH (diameter at breast height) of this tree. I am just shy of six feet. The log tapers quite quickly, though, but I still figure this douglas fir was between 3 and 400 years old when cut. Often old growth trees that are cut or fall in storms, or die of old age continue to lie around for many decades, perhaps a century, or more. They keep giving after getting horizontal, providing habitat and nutrients for hundreds of different species.