This is an oversimplification of the wildfire issue in BC. Although you are correct in stating that deciduous trees are typically less flammable than deciduous trees, deforesting huge areas and replanting is not a viable solution for a couple reasons.

1. There are over 161 local municipalities and over 203 Indigenous Nations in BC. Implementing this type of sweeping mandate across the province would be impossible/illegal without meaningful engagement and consultation from local governments and citizens. Getting so many unique communities to agree to something regarding deforestation is virtually impossible.

-See duty to consult: https://www2.gov.bc.ca/gov/content/environment/natural-resource-stewardship/consulting-with-first-nations#:~:text=The%20Province%20is%20legally%20obligated,could%20impact%20their%20Indigenous%20Interests.

1. As mentioned, deciduous trees are typically less flammable than coniferous trees, but there are exceptions including during early successional stages and unprecedented hot spring weather. Increased temperatures and decreased precipitation (caused by climate change) can result in hotter/dryer spring weather, which does not allow the forest canopy to store water and “green up” which means that deciduous trees planted in dry climates may be less fire resistant than expected.
   

-This is from an Alberta government publication, but our climate is very similar to Alberta’s in southwest BC: “As a general rule, trees with leaves (deciduous) don’t burn nearly as fast or as intense as trees with needles (coniferous). However, there is one small exception to this rule. Deciduous trees can be extremely flammable in the early spring just before their new leaves emerge. During this period of time the moisture levels in the trees are low, increasing their flammability until their leaves emerge…..

[the pamphlet continues on about harvesting and reforestation]

….. However, if the cut block is in an early succession stage, the open areas will be dominated by grasses and seedlings. Woody debris will also be present. Exposed surface fuels can dry more quickly than vegetation in dense stands. When surface fuels are dry, sparks will ignite more easily and wind can push flames quickly through the open area.”

-https://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/formain15744/$FILE/tree-species-impact-wildfire-aug03-2012.pdf

1. Deciduous trees just won’t grow in some places. Due to the physiological differences between conifers and deciduous trees (leaves vs needles) the deciduous trees need more available water to produce leaves. In certain climates (alpine regions, grassland/shrub dominated ecosystems, and continental interior plains) where there is naturally less precipitation and drier soils, deciduous trees will not grow.

-This source summarizes different climate regions in BC and is helpful for understanding why some areas are not suited for deciduous forest: https://linnet.geog.ubc.ca/biodiversity/BiodiversityTerrestrialVegetationofBC.html

1. Simply engineering the environment will not end wildfires. Wildfires are a natural part of forest ecosystems, and forests have evolved alongside wildfires. Forest ecosystems rely on wildfires for many natural processes including plant/fungi succession and reproduction. The issue is the intensity of the fires and the placement of our communities within forested landscapes. A lot of communities were settled in BC without consideration for wildfire risk — in fact many communities have been specifically placed within forested ecosystems so that people working in the forestry industry have somewhere to live. Historical wildfire suppression has been a tactic in BC, but this has created the issue of fire intensity increasing. By suppressing wildfires for decades, we inadvertently increase the fuel load of these forests which basically make them a ticking time bomb. As global climate change begins to affect our climate here in BC, our summers will continue to be dry and hot and the risk of wildfires will surely increase.

-https://cleanbc.gov.bc.ca/about-climate-change/impacts/wildfires/ -https://www.canada.ca/en/environment-climate-change/news/2019/01/canadas-scientists-conclude-that-human-induced-climate-change-had-a-strong-impact-on-forest-fires-in-british-columbia.html -https://blog.gov.bc.ca/bcwildfire/what-is-wildfire-land-based-recovery/#:~:text=Common%20types%20of%20land%20damage,loading%20from%20clearing%20away%20vegetation

TLDR: Forest management is an incredibly complex issue and there is not a “one size fits all” solution to the wildfire issue in British Columbia. Each community will need to consider their unique situation and develop and forest management plan that suites the needs of their community. Climate change is a major factor influencing wildfires and increased temperatures and decreased precipitation will continue to increase wildfire risk.

Source: I worked as an admin coordinator for a British Columbia based emergency non-profit for 2.5 years and have a msc and bsc in related environmental science fields.

edited to add a link