Growth of Giant Sequoia Compared to Ponderosa Pine and Other Mixed-Conifers in California Plantations

摘要

Giant sequoia (Sequoiadendron giganteum, SEGI) is a Sierra Nevada conifer famous for its supreme size, longevity, decay resistance, and visual appeal. A restricted natural range endangers SEGI to catastrophic wildfire and adverse climate change. Conservation aims to protect and restore extant native groves and to create new groves in promising forest environments. SEGI was compared to the best local conifer, usually ponderosa pine (PIPO), planted on 107 productive sites along western slopes of the Sierra Nevada and southern Cascades. SEGI had greater or similar ht and dbh as PIPO in more than 90% of the plantations. Best development and growth superiority of SEGI occurred in the southern latitudes (< 38.6° lat.), on high quality sites, and middle slopes with southwest aspects at low stand densities. SEGI increased in dbh superiority over PIPO linearly with stand age. On the southern latitude high quality sites, SEGI averaged 2.6 m taller and 22 cm larger in dbh than PIPO at age 50. SEGI incurred greater loss in dbh (compared to PIPO) from higher stand densities on southeastern aspects and high sites. Site elevation did not affect species comparisons. Warmer temperatures and higher precipitation differentially favored dbh of SEGI.