Accomplishing Forest Restoration with Biomass Harvesting Methods

Eagle Lake Ranger District
Lassen National Forest

Aspen Restoration

No information regarding the historic extent of aspen on the Eagle Lake RD has been discovered. However, District observations indicate that at least 50% of the historic extent of aspen has been lost. This loss is indicated by the presence of dead stands of aspen, and by many stands characterized by aspen skeletons greatly exceeding the current extent and density of live aspen. Over 80% of the existing aspen stands on the District are at high risk to being lost due to conifer invasion, excessive browsing or both. Approximately 91% of the aspen on the District will require treatment of conifers. Concern regarding aspen was first raised in a 1952 Lassen NF Inspection Report. This report stated that:

"….There has been no surviving reproduction of this species [aspen] on the Forest for many years. Even moderate livestock use appears to eliminate reproduction and we know that deer graze the species closely. The absence of aspen reproduction is also noted in Lassen National Park in areas where deer use appears to be only moderated. Our brief look indicated that, with present deer populations, it is probable that aspen will disappear form the Forest due to the absence of reproduction."

During the field season of 1999 the Eagle Lake RD began an aggressive aspen restoration program. In FY 2004 the District is planning to treat over 500 acres of aspen. The use of biomass harvest operations for conifer removal in aspen stands has proven to be the most effective method for restoring aspen regeneration.

Feather Lakes Aspen Enhancement Project

P3 - A tracked self-leveling feller buncher (shear) is operating within an aspen stand on the District

Bidwell Aspen Enhancement Project

P4 - Bidwell aspen enhancement project 6/29/99

Prior to any aspen treatments, the District establishes monitoring points within each stand to evaluate the effectiveness of the treatment. The photograph above was taken just prior to harvest activities during the establishment of the monitoring points. It is clear that very little aspen regeneration existed prior to treatment. Only one aspen tree can be seen in the stand, which is in the center of the photograph. There were well over 500 trees per acre of conifers prior to treatment. This aspen stand is approximately 9 acres in size.

P5 - Bidwell aspen enhancement project 7/25/03

Four years after treatment, the aspen regeneration has increased dramatically along with other understory vegetation. The aspen regeneration increased to 10,556 stems per acre from the 1,820 stems per acre prior to treatment*. That is the same aspen tree that was in the center of the previous photograph.

* Stem numbers are within sample plots. Not representative of the entire stand.