One of the greatest challenges with managing ecological systems is investing in patience. Large scale changes, both positive and negative often occur over many years, decades and even millennium. Oaks, in particular, grow very slowly, and the recovery of an oak savanna can easily take decades. This is often too long of a timescale even for long-term (5-10 year) restoration grants.
In contrast to annual financial balance sheets which expire after 365 days, nature takes too long. In some cases, quarterly reports rule, reducing time lines to about 90 days. Purely and simply, patience can be expensive especially when there are expectations of regular production.