Climate wobble

I am not totally on-board with man-made climate change but I do believe that the climate has internal feedback mechanisms that can cause weather to go over-center like a fat-kid on a teeter-totter and stay pinned there for prolonged periods.

In time, the fat-kid will lose enough weight that the teeter-totter will "behave" until another fat-kid sits on one side of the pivot or the other.

So it seems prudent to hedge ones' bets just like one might have more than one kind of investment in your retirement portfolio.

Drought tolerance

If you make a slightly more than causal review of the research, much of what is called drought tolerance are adaptive responses to wild-fires.

The thinking is that drought stress makes trees more vulnerable to diseases and bugs. Dry, standing dead-wood makes for wild fires. Some trees have adaptations that allow them to dominate after a fire. A short, incomplete list includes:

• Thick, fire-resistant bark
• The ability to throw up stems from the roots
• Latent buds at the base of the tree
• Wood that rots slowly so the tree doesn't succumb while a burn wound is healing over.
• Seeds that require heat before germinating
  

Some species have more than one strategy. Black Locust, for instance has thick bark in adults, throws up stems from roots, the wood rots slowly AND the seeds need exposure to heat to break-down the waterproof coating around them.

Other species (and gensus) are largely lacking these strategies except for a few rare individuals. Maples are an example of this.

Finding the rare individual

Suppose one were to engage in the Quixotic quest to produce a seedling orchard of southern oak species* that are tolerant of low-oxygen soils AND resistant to fire. These two characteristics rarely go together. Low-oxygen soils is code for "swamps" and wild-fires are a rare event in swamps. Oak species that grow in swamps are usually vulnerable to fire.

Southern North America is rich in oak species that are tolerant of flooded and low-oxygen soils: Overcup Oak, Willow Oak, Nuttall Oak, Water Oak, Pin Oak (palustris), Shingle Oak.

There are also some oak species that are notably resistant to fire: Bur Oak, Post Oak, Blackjack Oak, Gambels Oak, Shinnery Oak, Black Oak and in the north, Hills Oak.

One strategy would be to create hybrids of the two groups and then sort for flood tolerance and fire tolerance. 

Sometimes you will stumble across natural hybrids. Locally, there are trees that are intermediate in leaf characteristics between Shingle Oak and Black Oak. That might be an easy place to start.

How would you sort for fire-resistance?

One way is to snip the one-year-old seedling at ground-level which mimics what fire would do and to select the seedlings that are the quickest or most vigorous in their recovery. The individuals that have viable buds between the "seed-leaves" (cotyledon) and the surface or have the ability to throw shoots from roots should rise-and-shine.

Seeds are cheap. Growing them to adulthood before sorting them for stressors is expensive. The smart move is to find a way to sort seedlings at the youngest possible age. My thinking is that some individuals of "swamp species" might have genes lurking in the wood-pile from an earlier dalliance with a fire-tolerant species that might occasionally surface if you are looking for them.

The big win here is that snipping the seedlings near ground level increases the number of latent buds at the base (i.e. coppicing). So even if there is no discrimination between the seedlings, the snipped seedlings will, as individuals, have an enhanced bank of latent buds should they experience fire stress. It is analogous to root-pruning to increase the number of fine, feeder roots except it is to increase the individual's ability to recover from a fire.

*Southern species are likely to offer resilience to the stressors associated with wobble in the "hot" direction.