Ramnu

When Poul Anderson describes the planet Ramnu in A Stone In Heaven IN Anderson, Flandry's Legacy (New York, 2012), I have to google phrases like "climax forest" (p. 86) and "graviportal" (p. 87). (The latter sounds like a science fictional device: a portal between gravitational fields?)

How Plants Have Adapted To The Frequency Of Fires
deep roots or bulbs;
rapid reseeding;
"pyrasphales " or "nullfire" - ubiquitous plants like Terran grasses or Hermetian yerbs but synthesizing a silicon compound that makes them incombustible and that herbivores either excrete unchanged or break down with symbiotic microbes whereas earlier species unable to digest or excrete the fireproofing became extinct. 

How Organisms Have Adapted To Long, Cold Nights
some plants secrete antifreeze;
others make freezing part of their life cycle;
some exotherms sleep where they won't freeze or be dug up;
others "...start a new generation by sunset whose juvenile stage can survive." (p. 87)

Ramnuan Animals
are generally small because of high gravity;
if larger, have cooling surfaces like big ears, dorsal fins or wings;
are often featherless flyers, because the thick atmosphere offsets gravity, but usually keeping low because pressure drops swiftly with altitude;
if "pleurochladoi," have intermediate false limbs, "extensors," aiding locomotion;
sometimes have membranes on extensors for cooling and gliding.