Intense fire damage Greetings fellow Foxies,
I have been reflecting on the recent fire, which severely burnt sections of North Yilliminning and Birdwhistle reserves.
Most plants in our bush are adapted to fire, but both reserves had been unburnt for about 50 years and were littered with dead material, which fuelled a very hot fire.
Annual plant seeds on the surface or seeds retained on plants were obliterated. Survival of seed in the soil varies with depth of burial.
Woody root plants which regrow from soil lignotubers (most eucalypts) and root suckers should survive well and resprout in the next few months.
I have been reflecting on the recent fire, which severely burnt sections of North Yilliminning and Birdwhistle reserves.
Most plants in our bush are adapted to fire, but both reserves had been unburnt for about 50 years and were littered with dead material, which fuelled a very hot fire.
Annual plant seeds on the surface or seeds retained on plants were obliterated. Survival of seed in the soil varies with depth of burial.
Woody root plants which regrow from soil lignotubers (most eucalypts) and root suckers should survive well and resprout in the next few months.
Geophytes are fire tolerant perennial monocotyledons, which resprout from dormant underground storage organs each growing season - rhizomes, bulbs, corms and tubers.
The ability of geophytes to resprout at the break of the season enables them to outcompete annuals, and they survive hot and frequent fires. Unfortunately, many invasive weeds are geophytes, and some also have contractile roots, which draw them deeper into the soil. Introduced Guildford grass has spread through most loam and duplex soils at the expense of native annuals.
Rhizomes are swollen underground stems, which are very common in sedges, rushes, Haemodoraceae (kangaroo paws), and some native lilies. Depending on depth, rhizomes provide fire resistance, however in the absence of fire, rhizomatous plants can take over from plants that depend on fire for seed germination. The image below shows the effect of a hot fire in Foxes Lair after a decade. The left side (unburnt for decades) has mainly mature rock sheoaks with a dense sedge understorey. To the right, fire has stimulated a range of shrubs to grow from buried seed, and has reduced sedge density.
The ability of geophytes to resprout at the break of the season enables them to outcompete annuals, and they survive hot and frequent fires. Unfortunately, many invasive weeds are geophytes, and some also have contractile roots, which draw them deeper into the soil. Introduced Guildford grass has spread through most loam and duplex soils at the expense of native annuals.
Rhizomes are swollen underground stems, which are very common in sedges, rushes, Haemodoraceae (kangaroo paws), and some native lilies. Depending on depth, rhizomes provide fire resistance, however in the absence of fire, rhizomatous plants can take over from plants that depend on fire for seed germination. The image below shows the effect of a hot fire in Foxes Lair after a decade. The left side (unburnt for decades) has mainly mature rock sheoaks with a dense sedge understorey. To the right, fire has stimulated a range of shrubs to grow from buried seed, and has reduced sedge density.
Foxes Lair. Sedge dominant unburnt land on right , dense germination of mixed shrubs ten years after fire on left
Bulbs have a thickened stem base of modified leaves, which store nutrients. Examples include onions and introduced lilies such as daffodils, hyacinths, tulips, and Easter lily. Some Haemodorum species (bloodroots) are bulbaceous.
Haemodorum spicatum (bloodroot) bulb
Corms are swollen stem bases filled with starch, which sit on the root base. These are very common in native and introduced geophytes. Natives include many lilies, sundews, and triggerplants. Some of our most aggressive introduced weeds (oxalis, freesias, watsonia) are cormous.
 Easter lily weed bulb |  Freesia weed corms |  Watsonia weed corms |
Tubers (swollen storage organs which form on roots and underground stems) are present on all our orchids and many native lilies, and many are bush tucker foods.
Grass trees and zamias have above ground, fire resistant growing points called caudexes.
Grass trees and zamias have above ground, fire resistant growing points called caudexes.
 Chamaescilla corymbosa lily tubers |  Potato tuber |  New growth from caudex inside top of grass tree stem |
I will peg some spots in these reserves and see what comes up