Tuesday, October 15, 2013

26 years of monitoring at Reserve West -- from post-fire site to new forest

Another chapter in a 26-year saga has been written. A team of SNRAS people in a variety of positions completed an annual white spruce tree measurement exercise Oct. 10. The team measured all 2,251 white spruce in the Reserve West reference hectare, and 1,532 broadleaf trees in 40 percent of the plot.

After the 1983 Rosie Creek Fire, Dr. Glenn Juday (Professor of Forest Ecology), established the Forest Reference Stand network in Bonanza Creek Experimental Forest. Reference stands are 1.0 hectare (2.47 acre) or larger plots of forest that are monitored on a long-term basis. The Reserve West reference stand was a 200-year-old white spruce forest at the time of the 1983 fire. Starting in 1988 all white spruce in the hectare have been mapped and measured annually. The reference stand system in Bonanza Creek Experimental Forest is featured in a chapter in an upcoming research report on long-term ecological and silvicultural studies of the Global Institute of Sustainable Forestry and the Yale School of Forestry and Environmental Studies.
Kimberley Maher (left) instructs Christin Anderson on
use of the range pole for tree height measurement.

Over the years a number of students and staff have joined in for the Reserve West fall measurements. This year’s team included Research Technician Ryan Jess, Ph.D. graduate (2013) Kimberley Maher, Ph.D. student Miho Morimoto, M.S. Student Andrew Allaby, Temporary Technician Dashiell Feierabend, and new M.S. student Christin Anderson. Participants in previous years include Emily Sousa (Geography M.S. student), Steve Winslow (NRM B.S. and M.S.), Scott Sink (NRM M.S.), and Robert Solomon (research technician).

SNRAS crew at Reserve West after the
measurement of the last tree. From left,
Miho Morimoto, Andrew Allaby,
Feierabend, Ryan Jess, Glenn Juday
Reserve West tree measurements need to be made after the growth season is completed but before the arrival of snow. This year’s effort started in the last week of August and continued sporadically until early October. Each year the field crew measures the total height, that year’s height growth and the diameter at the base of the tree and at breast height (137 cm) of each white spruce tree. Each spruce tree is also evaluated for condition of the leader (many are nipped by squirrels), presence of spruce budworm, amount of canopy shade and other characteristics. Immediately following the 1983 fire the broadleaf trees and shrubs (birch, aspen, alder, willow) were so numerous and changeable that individual tree measurements were not practical. Individual stems would appear, be browsed back by moose, broken by snow loading, or shaded until dead – and then resprout.

The summer of 2013 got off to a slow start; ice breakup on the Tanana River was the second latest since 1917. Spruce at reserve West were carrying a good load of foliage needles, particularly because of the cool and moist summer of 2012, which provided substantial relief from the moisture stress of the frequent warm summers of the last 30 years. But once it did start, the summer of 2013 was hot and dry. One result was the appearance of “needle dumping,” the shedding of excess older retained needles that are a liability during periods of extreme moisture stress.

The reddish brown needles on this white spruce at Reserve West represent the simultaneous loss of marginal old and partially shaded foliage, possibly stimulated by the prolonged extreme warmth during the summer of 2013.

Weather during the fall measurement season was a bit of a roller coaster. The first part of the measurement period had generally below-normal temperatures. The arrival of slushy snow on September 17, 20, and 23 had the usual effect of stimulating the last stage of the measurements. Then on Sept. 25 above-normal temperatures arrived and stayed until mid-October.

The tallest white spruce trees now exceeded the height of the extendable rangepole (765 cm or 25 ft) that was sufficient in the past, so a laser height measurement device (hypsometer) with a tripod mount was used. Repeated laser height measurements were taken to verify that the required precision in height measurements was being achieved.

This fall most of the participants agreed – even though there are still a few treeless openings at Reserve West, it is no longer a “post-fire” site, it’s a young forest. This phenomenon is the leading edge of a wave of similar developments that might be expected as a result of successional forest growth and development on the vast areas that burned in the fires of 2004, 2005, 2009 in boreal Alaska – cumulatively over 14 million acres. In effect, Reserve West and the other burned reference stands of Bonanza Creek Experimental Forest could be an early look at what similar productive sites that were burned in these more recent major fire years would look like themselves in 30 years – from 2034 to 2039. Or at least what they would look like if we lived in a world of limited environmental change and an essentially steady climate. But that does not appear to be the kind of world we, or the new forests, do in fact live in.

From a forester’s or ecologist’s perspective, the growth of a new forest spans such lengths of time that it always amounts to an encounter with the unpredictable, the unknown and unknowable. Nearly 30 years ago, after the 1983 Rosie Creek Fire that regenerated the stand at Reserve West, I reflected on some of these themes at the end of an article on the Rosie Creek Fire suppression effort and its immediate aftermath.
And so the Rosie Creek Fire ended – not with a bang, but a whimper. The loss was nearly $5 million in direct suppression costs and lost timber value. Several harvest areas with young regeneration, still rare in interior Alaska, had been lost. Nearly one-third of the Bonanza Creek Experimental Forest had been burned. A major subdivision had been threatened.

On the other hand, a new laboratory/demonstration area for reforestation was created right next to other, continuing forestry projects. Grasses and aspen trees were sprouting within a matter of days after the fire, and moose were beginning to move into the area. Nature was setting the stage for the growth of a new forest, another link in an unbroken chain of renewal which led to this day. But this time man was planning to be a partner in the development of the new forest. One can hope that we will be a sensitive and constructive partner. Our success will be judged by future generations.
As we reach the quarter century mark of research at the Bonanza Creek Long Term Ecological Research Site, as a new and rapidly growing demand for forest biomass energy in the last few years is met, and as the climate of Alaska continues to change, the answer to the question of that partnership remains in the balance.


Juday, Glenn P. 1985. The Rosie Creek Fire. Agroborealis 17(1): 11-20.

This post was contributed by Professor Glenn Juday. Photos courtesy Glenn Juday.

Further reading:
Tree measurements at Reserve West beat the arrival of snow - again, SNRAS Science and News, Oct. 29, 2011

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