Early stages of Calluna vulgaris regeneration after burning of coastal heath in central Norway

Abstract

Questions: How does Calluna vulgaris regenerate after burning wet and dry heaths of different age? Location: Central Norway. Methods: Patches of Calluna dominated old and young wet heath and old dry heath were burned. The mean temperatures reached in the categories of heath were measured. Cover, frequency, height and number of seedlings of Calluna were studied in plots. Results: The mean burning temperatures varied from 680 to 740°C, and were highest in wet heath that had not been burned for at least 50 years. Regeneration of Calluna was evident in the year of burning, but only from seeds. Even heath with a short burning interval lacked vegetative regeneration. Calluna cover increased yearly and exceeded 50 % three years after burning. Regeneration was evident in the year of burning, and was highest in heath with a short burning interval. The height increased regularly at all sites, but was most rapid in dry heath, probably because of better microclimatic conditions. There were more seedlings in the heath with a short burning interval. Conclusions: Calluna only regenerates from seeds afterburning in central Norway. The density of Calluna increased rapidly, which is positive for the conservation and management of coastal heaths in central Norway.

The colors of heath flowering – quantifying spatial patterns of phenology in Calluna life‐cycle phases using high‐resolution drone imagery

“…The effectiveness of fire management for the restoration of degenerated Calluna thus depends on the establishment of seedlings, which is additionally determined by characteristics of the implemented fires themselves (such as duration and temperatures), post‐fire substrate type or soil moisture (Whittaker and Gimingham ; Grant ; Nilsen et al. ; Matt Davies et al. ).…”

The age of Calluna stands moderates post‐fire regeneration rate and trends in northern Calluna heathlands

“…one ewe per 2 ha) graze year‐round in the study area. In the study area, vegetative regeneration from Calluna has been shown to be absent in young as well as old Calluna stands (Nilsen et al 2005).…”

“…Minimum distance between blocks was set at 20 m. Fires were set between February and April under appropriate weather conditions, i.e. sufficient wind to carry the fire onwards and with frozen or wet ground (the mean fire temperatures range from 680 °C to 740 °C, see Nilsen et al 2005). Within each block, two 1‐m 2 plots were placed randomly and permanently marked with metal poles, avoiding marked depressions and concavities and areas with >10% bare rock or bare soil, >20% faeces, <4 m from edge of burned area or adjacent to another plot, and incompletely burned vegetation.…”

“…The controls, analysed in 2002, were used throughout the time series. This was considered valid because an RDA performed on control plots from nearby blocks analysed in 2000–2003 revealed no significant effect of time [ P =0.996, n =24; data from Nilsen (2004)].…”

“…Consequently, the regeneration rate, and hence the restoration potential, of late‐successional heaths has been regarded as low, leading to the recommendation that young heaths should be prioritized for conservation management (see Davies et al 2010). Interestingly, a study from northern heathlands found no vegetative regeneration, even in relatively young heath (Nilsen et al 2005), and Calvo et al (2002) considered Calluna to be an obligate seeder in alpine areas in northwest Spain. This apparent lack of vegetative regeneration implies that management recommendations based on studies from a warmer climate, where vegetative regeneration is dominant, are likely to be of little relevance in northern latitudes and higher altitudes.…”