TRENDS IN FIREWOOD HARVEST

---

As mentioned before, the California Department of Forestry and Fire Protection has conducted aerial monitoring of firewood harvesting over the past three years. Most of the principal hardwood rangeland counties in the state were surveyed three times over the four year period. This survey data was designed to show general trends in harvest and the level of canopy reduction which occurred. This was not inclusive of all harvests in hardwood rangeland areas, but was felt to include most major acreages cut. Aerial observers estimated pre-cut canopy cover of harvested areas by comparing the adjacent uncut areas, post-cut canopy cover, and acreage of harvest. Locations were recorded which allowed cuts to be located spatially on the CDF Hardwood Rangeland CIS. Some harvest areas were undoubtedly missed in this survey. It was felt that light harvests would quite possibly not be discernible from the aircraft.

Table 1 shows the general harvest levels over the four years in which the aerial monitoring was conducted. Cords harvested were estimated by converting crown cover before harvest and after harvest to volume using the relationships described in Standiford and Howitt (1989). This shows that 27,000 acres had some harvest, with almost 315,000 cords harvested. This is no doubt a low estimate of hardwood rangeland cordwood harvested given the conservative nature of the aerial monitoring described above. Over 50 percent of the cords harvested in the state were in Shasta and Tehama counties alone, although these two counties represent less than 10 percent of the hardwood rangeland acreage in the state.

On a general regional analysis, there did not appear to be a major impact to the hardwood rangeland resource as a result of firewood harvest, with the exception of Shasta and Tehama counties. Overall, about 0.1 percent of the total hardwood rangeland acreage had firewood harvesting. There is still some concern since the level of harvest in these areas exceeds the recommendations of the IHRMP's Preliminary Guidelines for Managing Hardwood Rangelands (Passof et al, 1986), and the Fish and Game retention standards in 96 of the 120 firewood areas surveyed. This may create some locally significant impacts in some watersheds and will be investigated in more detail in upcoming landscape analysis of harvest areas. Since the light partial cutting recommended by IHRMP educational documents was probably not included in the sampling, this may not accurately reflect typical harvest practices (see results of the educational program section above).

Since the level of harvest in Shasta and Tehama counties was so much higher than the rest of the state, a preliminary estimate of the cut versus growth was made to determine the sustainability of current hardwood rangelands. Harvest was assumed to take place on private land acreages since virtually all harvest occurred on private land. Crown cover was converted to volume in cubic feet and cords as described above. The growth of each of the four canopy classes in the CDF Hardwood Rangeland CIS was estimated using general growth equations developed by Standiford and Howitt (1989). Growth per county was developed by multiplying growth per canopy class times acres per class. An annual accounting was made to shift acreage from its precut canopy class to postcut canopy class. Since two of the sampling periods were longer than one year, growth was adjusted accordingly.

This general analysis showed that for Tehama County, cut approximately equals growth on private lands. Private hardwood rangelands in that county are currently at close to their productive potential at this time. In Shasta County, cut has exceeded growth by 30 percent over the four year period. Current levels of harvest will gradually decrease the volumes, and hence canopy cover, of private hardwood rangelands.

Table 1. General summary statistics of CDF aerial monitoring of hardwood rangelands over 4-year period (Fall 1988 to Fall 1992) for the four CDF regions.

Harvest Characteristics Region 1 Region 2 Region 3 Region 4 Totals Shasta/Tehama Other Co. Cords 19,142 142,982 47,164 7,251 97,527 314,066 Acres 1,906 15,025 4,225 490 5,505 27,151 Precut Crown Cover 49% 53% 55% 58% 76% 58% Postcut Crown Cover 13% 15% 8% 22% 33% 18% Number of Harvests 24 40 17 9 30 120 Annual % Acres Harvested 0.03% 0.41% 0.12% 0.01% 0.03% 0.08% 4 Year Growth (cords) 129,969

Implications

This preliminary analysis shows that on a statewide basis, a relatively small percentage of hardwood rangeland acreage is harvested. There is a downward trend in the annual acreage harvested, at least partially due to the attention given to the negative environmental effects of complete tree removal. However, with the relatively low growth of hardwood rangelands, coupled with large acreage of harvest units and heavy canopy reduction in Shasta and Tehama counties, a renewed attention to the impact of firewood harvesting is needed in this area. CDF is funding the development of a "Sustainable Landscape" project in the Northern Sacramento Valley to allow the cumulative impacts of this level of harvesting on water quality and wildlife habitat to be evaluated on a landscape or watershed basis. Some preliminary discussions between local agency resource managers, agricultural groups, and environmental groups have taken place to develop strategies to reduce the level of harvest in these two counties. The "Sustainable Landscape" project will allow local people to evaluate the impacts, and determine the appropriate policy actions to be followed.