Chimneys are easy to neglect. Some are external to the homes they serve. They occupy visible but minor garden space. Others are internal. Only portions that extend above their respective roofs are visible. Besides the use of accompanying fireplaces or woodstoves, they do not change with the seasons. Nonetheless, chimney clearance is very important.
Trees and vines often extend growth over the tops of chimneys. They grow most actively while chimneys are least active through spring and summer. Such growth is hazardously combustible within the exhaust of chimneys below. Essential chimney clearance pruning eliminates hazardous vegetation prior to the use of associated fireplaces or woodstoves.
Various eucalyptus, cypress, pine, cedar, juniper, fir, spruce, oak and bearded fan palms are very combustible. Deciduous oaks become less combustible as they defoliate during cooling weather though. Other deciduous vegetation is likewise less combustible by the time chimneys are most in use. Vines can accumulate debris directly on top of chimneys.
Vegetation within ten feet of a chimney should generally be two feet below the top of the chimney or fifteen feet above it. More combustible vegetation justifies more clearance or more vigorous grooming. Accumulated dry detritus is more hazardous than fresh foliage. Burning vegetation drops burning debris onto other combustible vegetation and material.
Of course, fireplaces, woodstoves and their associated chimneys are not as common as they were in the past. Most municipalities banned them from new construction during the past many years. Removal of chimneys that incur damage from earthquakes is generally more practical than repair. Chimney clearance becomes unnecessary without chimneys.
Furthermore, few surviving chimneys experience as much use as they did decades ago. Modern heating systems are much more practical and efficient. They generate no smoke to offend neighbors. They are unregulated by ‘no-burn’ alerts. Now that urbanization has replaced orchards and woodlands, firewood might be expensive from local tree services.