Andrew Larson, Seattle Public Utilities

Andrew Larson works in the Watershed Management Division of Seattle Public Utilities as a forest ecology intern. He is also pursuing graduate studies in Forest Ecosystem Analysis at the University of Washington.

This morning I'm finishing up some loose ends in the office before I head out to the field. I'm particularly excited about one task on my to-do list: I need to contact Dr. Robert Van Pelt, the world expert on big trees.

Last Thursday I went out with Dr. David Chapin, who works in the fish and wildlife group here at the watershed, to measure two huge noble fir trees he discovered growing along the upper Cedar River. Noble fir (Abies procera), which grows only in Oregon and Washington, is the largest true fir species in the world. All of the current record noble firs grow near Mt. St. Helens in southern Washington. David's descriptions of the trees he found sparked my imagination: Could we have record-sized noble fir growing in the watershed? We decided an expedition to collect detailed measurements of the monster trees was needed.

I met David in the field Thursday afternoon. We parked at the edge of an old-growth stand I had driven past many times. I wondered to myself if David had remembered the right location; the trees in this stand were nice enough, but I knew of dozens of other places in the watershed with larger trees. We jumped out of the vehicles and loaded up our gear. We brought a GPS unit to record the locations of the trees, a laser to measure their exact heights, tape measures to measure the stem diameters and crown widths, and, of course, digital cameras to substantiate our measurements (and bragging rights).

As we descended from the road into the stand I still had my doubts. These trees were really rather small. I'm glad now that I kept these doubts to myself. As we moved downhill toward the river, the trees started to get bigger, and bigger, and bigger! By the time we reached the river floodplain terrace we were in a spectacular old-growth forest of monster Douglas fir, western hemlock, and western red cedar. This was easily the most impressive stand of trees I had seen in the watershed.

We were still a couple hundred feet away when the first of the two noble fir came into view. The tree towered above its neighbors. The massive stem looked completely out of place, even in this awesome stand of very respectably sized trees. I quickly pulled a tape around the base of the tree. It measured 6.7 feet in diameter. Right away, I knew this tree was not a new record, but it was impressive nonetheless. We collected the rest of the measurements and set off to find the second noble fir. Within minutes we found it. At 7.0 feet in diameter and 220 feet tall, this one was larger than the first, but still not a new record.

These two noble fir may not be the largest in the world at this particular moment, but they stand an excellent chance of becoming serious contenders in the future. Crown size is often a good index of tree vigor and growth potential. The crowns of these two not only dwarf their neighbors, they are the biggest noble fir crowns I have ever seen! Also, unlike most old-growth trees, these two noble fir show very little damage to their crowns, indicating that they are probably comparatively young, for old-growth, and will continue to grow for centuries. I suspect Bob Van Pelt will want to hear about these new discoveries, and I want to know where they fit into the current ranks of giant noble fir!

Unfortunately, life isn't all giant trees and old growth. I'll head out to the field soon to check in with the contractors that we have working on a current forest restoration project. In general, our contractors are excellent, but because our restoration thinning prescriptions are often quite different from the type of work the contractors are used to doing, questions frequently arise. After checking in with the crew, I'll hike through the thinned areas, putting in sample plots to characterize the post-thinning forest. These plots serve a dual role in our monitoring program. Immediately, we use the results to check that the contractors are in compliance with the prescriptions detailed in the contract. These sample plots also provide a "snapshot" of immediate post-thinning conditions across the treated area, complementing information from other long-term monitoring plots in the stand.

I may not have an excuse to spend today exploring old-growth forests in search of giant trees, but I still can't complain. For me, spending a good part of the day in any type of forest is a treat.