A tree species replacement sequence for dry broadleaved forests (tropical hardwood hammocks) in the upper Florida Keys was inferred from species abundances in stands abandoned from agriculture or other anthropogenic acitivities at difkent times in the past. Stands were sampled soon after Hurricane Andrew, with live and hurricane-killed trees recorded separately; thus it was also possible to assess the immediate effect of Hurricane Andrew on stand successional status. We used weighted averaging regression to calculate successional age optima and tolerances for all species, based on the species composition of the pre-hurricane stands. Then we used weighted averaging calibration to calculate and compare inferred successional ages for stands based on (1) the species composition of the pre-hurricane stands and (2) the hurricane-killed species assemblages. Species characteristic of the earliest stages of post-agricultural stand development remains a significant component of the forest for many years, but are gradually replaced by taxa not present, even as seedlings, during the first few decades. This compositional sequence of a century or more is characterized by the replacement of deciduous by evergreen species, which is hypothesized to be driven by increasing moisture storage capacity in the young organic soils. Mortality from Hurricane Andrew was concentrated among early-successional species, thus tending to amplify the long-term trend in species composition. iEy wad: drew; &af phenology; succession.

Summary1 Both ®re regimes and the conditions under which ®res occur vary widely. Abiotic conditions (such as climate) in combination with ®re season, frequency and intensity could in¯uence vegetation responses to ®re. A variety of adaptations facilitate post-®re recruitment in mediterranean climate ecosystems, but responses of other communities are less well known. We evaluated the importance of climate by comparing sites with mediterranean and subtropical climates. 2 We used paired burned and mature sites in chamise chaparral, mixed chaparral and coastal sage scrub (California), and rosemary scrub, sand pine scrub and sandhill (Florida), to test whether (i) patterns of pre-®re and post-®re seedling recruitment are more similar between communities within a region than between regions, and (ii) post-®re stimulation of seedling establishment is greater in regions with marked ®re-induced contrasts in abiotic site characteristics. 3 Post-®re seedling densities were more similar among sites within climatic regions than between regions. Both seedling densities and proportions of species represented by seedlings after ®res were generally higher in California. 4 The only site characteristic showing a pre-®re±post-®re contrast was percentage open canopy, and the eect was greater in California than in Florida. Soil properties were unaected by ®re. 5 Mediterranean climate ecosystems in other regions have nutrient-poor soils similar to our subtropical Florida sites, but show post-®re seedling recruitment patterns more similar to the nutrient-rich sites in California. Climate therefore appears to play a more major role than soil characteristics.

Abstract. This study deals with a quantification of pre‐ and post‐fire seedling establishment and microsite characteristics in two Florida sand pine scrub sites burned in May 1993. In addition, life history characteristics related to seedling establishment are described for five perennial species –Calamintha ashei, Chapmannia floridana, Eriogonum floridanum, Garberia heterophylla and Palafoxia feayi. Post‐fire seedling establishment in sand pine scrub was sparse (median = 1, 12 seedling/m2), with 17 of 35 species establishing seedlings. Chapmannia, Eriogonum, Garberia and Palafoxia resprouted and flowered after fire; Eriogonum and Garberia had strong post‐fire seedling establishment responses within 19 months post‐fire. Calamintha individuals were killed by fire, but this species had a strong post‐fire seedling establishment response, presumably from seeds in a soil seed bank. Eriogonum and Calamintha seedlings established preferentially in plots centered on conspecific adults. For these species with poor seed dispersal, spatial patterns of seedling establishment may be influenced more by pre‐fire adult plant location than by post‐fire microsite conditions. Post‐fire seedling density in sand pine scrub was much lower than in California chaparral and South African sand plain lowland fynbos.