![]() ![]() įire-adapted traits including obligate seeding, resprouting, and fire-related germination cues are more in common in flammable than low-flammability forests where more plants regenerate independently of fire. ![]() Areas of mixed forest which have been burnt more severely and in closer proximity of a sclerophyll seed source will tend to regenerate towards sclerophyll dominated forest. and Hill and Read found that areas containing predominately rainforest species which can survive a patchy moderate fire will regenerate towards rainforest. However, this invasion is more commonly observed in areas of mixed forest than CTRF. As fire frequency and severity increases, CTRF becomes more open and can be invaded by light and fire tolerant species. Increased foliage cover from broad-leaved rainforest species alters fuel conditions and microclimate at ground level, providing an increasingly fire-suppressive environment. reporting 45% of Nothofagus cunninghamii and Atherosperma moschatum capable of resprouting following top kill by wildfire. For example, CTRF canopy species can resprout at high rates after fire with Trouvé et al. Rainforest species support several traits that confer increased resistance and resilience to fire, including reduced leaf flammability and resprouting abilities. The mix of species from both wet forest and CTRF can help slow and cool fires as they progress towards CTRF. Mixed forest is considered critical to the persistence of CTRF. Ĭool temperate mixed forest often forms an ecotone between wet forest and rainforest and can provide a degree of protection to cool temperate rainforest (CTRF) from processes such as fire that maintain the adjacent wet forest. ![]() Frequent, high-severity fire in sexually immature stands (200 years) may also result in forest transition, from eucalypt-dominated, wet sclerophyll forest to cool temperate mixed forest-where eucalypt canopies support rainforest understories and eventually cool temperate rainforest. Fires of low- to moderate-severity can produce multi-cohort stands, retaining biological legacies such as large trees. The predominant disturbance high-severity and infrequent stand-replacing fires that produce even-aged stands of Eucalyptus regnans. In contrast, the understorey regenerates from a soil seed store with succession following the initial floristics model of Egler. Eucalyptus regnans is an obligate seeding overstorey tree that is typically killed in high intensity fire, and regenerates from a canopy stored seedbank. Both smoke treatments had little influence on floristics in the germinated seed bank suggesting other, non-fire disturbances such as treefalls and soil turnover by fauna may be more important for germination for many of the species in these forest types.įire severity and frequency drives forest succession in the Mountain Ash ( Eucalyptus regnans) forests in the Central Highlands of south-eastern Australia. Forest type was a stronger determinant of floristics in the germinated soil seed bank than simulated fire related germination cues. Given the lack of response to karrikinolide, response to soil disturbance would most likely be associated with mechanical seed abrasion and/or exposure to increased light availability than to non-fire related production of smoke products. Endozoochores were concentrated (albeit at low densities) in cool temperate rainforest with no overall effect of seral affiliation on response to fire cues. Phanerophytes and ant-dispersed species with hard seed coats demonstrated positive response, and endozoochores negative response, to high heat independent of smoke. There was no overall response of species richness, abundance, or composition to fire cues. Response to fire cues was consistent among forest types despite underlying differences in the diversity of soil seed banks. Soils were placed in a glasshouse and germinants were identified and counted at weekly intervals. Soils from five replicates of each forest type were subjected to very low (45 ☌), low (65 ☌) and high (90 ☌) heat with or without two different smoke treatments: –smoke-infused vermiculite, and karrikinolide-a phytoreactive compound derived from smoke. We assessed the effects of heat and/or smoke on the soil stored seed banks across an ecotone of eucalypt to rainforest overstorey comprising wet forest, cool temperate mixed forest, and cool temperate rainforest in south-eastern Australia. Response to fire related germination cues often reflect historical fire regimes and can be important in maintaining ecotones between different forest types. Soil seed banks play an important role in plant species persistence in fire-prone systems. ![]()
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