There is an increased risk for these larger exposed trees to blow down during windstorms than for the somewhat smaller trees currently left (Alternative 3) on these types of sites.
(these larger exposed trees; to blow down; T:during windstorms than for the somewhat smaller trees currently left (Alternative 3) on these types of sites) (the somewhat smaller trees; left; T:currently)
these larger exposed trees the somewhat smaller trees
to blow down left
T:during windstorms than for the somewhat smaller trees currently left (Alternative 3) on these types of sites
T:currently