Underplanting is a practical silvicultural method for regenerating and diversifying conifer stands in Britain

There is a strong policy move in Britain to improve forest resilience to climate change by increasing stand structural and species diversity. Although currently little used in Britain, the technique of underplanting allows regeneration and diversification of stands while avoiding some of the disadvantages of clearfelling. Two experiments were examined: (1) the growth and survival of five underplanted conifer species of differing shade tolerance in a shelterwood and (2) compared performance of underplanted and open-grown Douglas-fir seedlings on restocking sites. Underplanted Sitka spruce, Norway spruce, noble fir, European silver fir and Douglas-fir were all able to survive and grow. However increased exposure following overstorey removal resulted in some damage and ‘socketing’, especially to taller seedlings, particularly Douglas-fir. This may be linked to poor root development when growing under an overstorey. Microclimate conditions on some underplanted sites were more sheltered from extreme climatic conditions, and in some cases this improved survival of Douglas-fir seedlings. However, seedling growth rates were reduced compared with those on open sites probably due to lower light levels. Underplanting may help to improve establishment success of some species, particularly in exposed areas. However, the shelter benefits of underplanting must be carefully balanced against the trade-off with lower light, and underplanting is likely to be more successful where low canopy density is maintained.

Returns from the Management of Noble Fir Stands for Bough Production and Sawtimber

Noble fir (Abies procera Rehder) bough harvest has been part of the nontimber forest products industry in the Pacific Northwest for decades. The boughs are used for seasonal decorations and command a higher pricethan most other decorative bough species. However, noble fir boughs that are harvested in the region have been merely a byproduct of noble fir plantations managed for timber products. This article presents the results of a study assessing the financial desirability of managing noble fir plantationsin the southern Cascade Mountains of Washington State for the production of both timber and bough products. The Landscape Management System software program was used to simulate the growth of noble fir in four different plant associations on the Gifford Pinchot National Forest. Data from recentlyestablished noble fir plantations were used in the simulations. Harvestable bough weights were estimated using a previously published noble fir bough weight model. Comparisons of estimated harvest volumes for sawlogs and noble fir boughs showed positive present net worth (PNW) values for eachstand under a combined timber production and bough harvest scenario and negative PNW values for each stand with a timber production management scenario only. Bough harvest is compatible with other land use activities, and the harvest revenue can cover stand establishment and precommercialthinning costs.

Geographic variation in chloroplast haplotypes in the California red fir-noble fir species complex and the status of Shasta red fir

I present the results of a molecular investigation into taxonomically unresolved issues of the California red fir – noble fir species complex. Samples were collected throughout the range of California red fir ( Abies magnifica A. Murray), from the southern Sierra Nevada to the region in northern California and southern Oregon where morphological variation has suggested it hybridizes with noble fir ( Abies procera Rehder). Two rbcL sequences were found within A. magnifica and showed perfect linkage with variation at the chloroplast trnD locus. Only populations in the region of hypothesized hybridization were polymorphic for rbcL. One haplotype is unique to A. magnifica in the southern part of its range, and the other is identical to that found in A. procera to the north, supporting a broad zone of hybridization. There was no evidence for a cryptic geographic barrier between the two species. A single A. procera tree from southwestern Washington also had the A. magnifica haplotype, suggesting that introgression from A. magnifica may be widespread. The type locality of Abies magnifica var. shastensis Lemmon was polymorphic, whereas the disjuct southern A. magnifica var. shastensis was monomorphic for rbcL. I also present corrections, based on replication, to two rbcL sequences for A. magnifica previously deposited in GenBank.