For example, fire can eliminate pest populations or resting fungal spores that could infect new seedlings. Low intensity burns can also clear space in the understory and provide nutrient pulses that benefit the understory vegetation. Fire is also used to prevent "fuel" buildup, the highly flammable plants such as grasses and scrub under the canopy which could burn easily in a wildfire. Most prescribed burn intervals are about every 2–5 years which allows the ecosystem to regenerate post-burn. Much of the South Florida Pine Rockland ecosystem is highly fragmented and have not been burned because of the proximity to businesses and homes. Risks such as smoke, air quality, and residual particulate matter in the environment pose safety issues for controlled burns near homes and businesses. Starting in the late 1950s the emergence of Fusiform rust on South Eastern pine trees including slash pine ("Pinus elliottii)," loblolly pine, ("Pinus taeda)", and longleaf pine, ("Pinus palustris)" led to massive tree mortality within the pine industry. This obligate parasitic pathogen is notorious for infecting young trees in newer planted areas within the first 1–5 years of growing. The pine industry was still rather new at the time of this initial outbreak, therefore, many newly planted forests had large-scale mortality because the trees were not yet old enough to be resilient to the disease or harvested. Florida’s pine industry in particular was booming with an increase in plantation acreage from in 1952 to upwards of in 1990. Because of the complicated lifecycle of "Cronaritum quercuum f. sp. fusiforme", the fungal causal agent of Fusiform Rust, the management strategies of pruning diseased stems, reducing fertilization, and discarding infected seed were not sufficient enough to prevent million dollar annual loses. Rust pathogens are difficult to manage because of their complicated reproductive life cycles. "Cronaritum querecuum f. sp. fusiforme" is heteroecious, requiring two different plant hosts for reproduction, and is macrocyclic, meaning it contains all five spore stages typical for rust infections: basidiospores, teliospores, urediniospores, aeciospores, and spermatia. Oak trees are the secondary host for this pathogen. The primary inoculum on pine are basidiospores which infect the pine needles in spring between March and May. The basidiospores germinate and grow into the stems of the tree where the fungus can overwinter for 4–6 months in the wood.