Plants with (Alternative) Benefit(s)
Keywords: carbon source, carbon sink, photosynthesis, carbon sequestration, hydrological restoration, wildlife habitat
To select appropriate plant material, landscape horticulturalists need to consider the potential benefits of plants to humans and, more importantly, to the wider ecosystem network.
Landscape horticulturalists can look to their local and natural ecosystems for examples of how to effectively select plants and manage landscapes. Let’s first look at the role of forests, also known as the lungs of the earth, as an example of the ecological roles and benefits of plants.
“Forests can act as either carbon sources or carbon sinks.
- A forest is considered to be a carbon source if it releases more carbon than it absorbs. Forest carbon is released when trees burn or when they decay after dying (as a result of old age or of fire, insect attack or other disturbance).
- A forest is considered to be a carbon sink if it absorbs more carbon from the atmosphere than it releases. Carbon is absorbed from the atmosphere through photosynthesis. It then becomes deposited in forest biomass (that is, trunks, branches, roots and leaves), in dead organic matter (litter and dead wood) and in soils. This process of carbon absorption and deposition is known as carbon sequestration” (Government of Canada, 2022).
Video credit: How Trees Capture and Store Carbon, (The Woodland Trust, 2021)
“Climate change is expected to have a profound impact on the carbon balance of Canada’s forests. The biggest short-term impacts will result from changes in disturbance regimes. For example, scientists at Natural Resources Canada’s Canadian Forest Service predict that the forest area annually burned in Canada is likely to double by the end of the century, resulting in large emissions of carbon.
More frequent and longer-lasting droughts are expected to contribute to this increase. Similarly, increases in the area and intensity of insect outbreaks are expected to cause carbon losses. Already, climate change, in the form of warmer winters, has contributed to the major infestation of the mountain pine beetle in British Columbia and its recent spread over the Rocky Mountains into Alberta. A key question is whether the insect will be able to expand its range through Canada’s boreal forests.
Some aspects of climate change, such as longer growing seasons or greater concentrations of carbon dioxide in the atmosphere, are expected to increase tree productivity (at least initially). A warmer, wetter climate may also enhance decomposition rates. Northern regions of Canada are expected to warm faster than more southerly areas, resulting in the melting of permafrost; this may release methane from frozen soils and initiate the decomposition of previously frozen organic carbon” (Government of Canada, 2022).
Now, let’s take a look at an example from Foresty, a horticulture-adjacent industry for factors to consider when making land management decisions and th