Even as autumn weather cools, smoke rising from a simple old fashioned brick chimney is a rare sight nowadays. A smoking stovepipe is rarer. Modern building codes forbid the installation of new fireplaces or wood stoves within most municipalities here. Modern air quality ordinances severely limit the use of existing fireplaces and wood burning stoves.
Furthermore, existing fireplaces and wood stoves are neither as popular nor as common as they had been. After an earthquake, a faulty chimney is likely to justify removal rather than repair. An unused wood stove wastes too much space. Old orchards that generated inexpensive firewood as they relinquished their space to urban development are extinct.
There are a few advantages to these modern trends though. Modern homes consume so much less energy for heating than older homes because of efficient insulation. Insulation of older homes retains heat that fireplaces generate, so that less wood is needed. Almost every surviving chimney has a spark arrestor. Modern roof materials are noncombustible.
Nonetheless, vegetation that gets too near to a chimney that is in use can be hazardous. Even if clearance was adequate last winter, trees, vines and large shrubbery grew since then. It does not take long for such vegetation to overwhelm a chimney, or encroach a bit more than it should. It does not take too much vegetation to be hazardously combustible.
Clinging vines like English ivy and Boston ivy sometimes climb up and then over the top of a chimney. Although not especially combustible, they will burn directly over a fireplace or wood stove. Just like gutters do, vines can accumulate leaves that fall from deciduous trees to become more combustible. Birds or rodents can build combustible nests in them.
Evergreen trees and big shrubbery are similarly combustible over a chimney. Deciduous trees are generally not as hazardous. Conversely, cypress, pine, cedar, eucalyptus, large junipers, and ungroomed palms are very combustible. Eucalyptus foliage will burn while fresh, if it gets hot enough. The other trees tend to accumulate very combustible detritus.