story identification - A book from the 60s or 70s about a crashed spaceship and their colony

I read these books in the late 60s or 70s. There were two books in the series. I don't remember the author or titles.

There is a war between humans and aliens. A human ship crashes on a unexplored planet. They struggle to survive and live in a bunch of caves. One of the politicians refuses to work and is finally executed for hoarding. There is native life on the planet. A wolf-like species battles the humans but eventually they are found to be sentient and a truce is made. Another alien is a gopher-like creature that is telepathic and can relay messages.

After many years the humans, wolves and gophers live in harmony. Then an alien spaceship lands on the planet. The humans and their allies kill the aliens and take over the ship. The second book is about them going out and conquering the alien empire and rescuing the human planets. It has a little of the flavor of Poul Anderson's The High Crusade.

Answer

This is Tom Godwin's Ragnarok series comprising The Survivors (aka Space Prison)—there is a Wikipedia article and a Project Gutenberg etext—and its sequel The Space Barbarians. However, the humans in Godwin's story do not crash-land on the planet; they are marooned there by the enemy aliens. Otherwise, it is just as you described it. Here is the back cover blurb from my copy (Space Prison, Pyramid Books, Feb. 1960 printing):

DOOMED

Crushing gravity—thin air—winters
of unimaginable cold—searing summers under
two suns—a deadly wasteland teeming
with monsters and killing fever—

That was Ragnarok, the most dreaded
planet yet discovered. And Ragnarok was
where a thousand untrained Earthmen—and
women and children—were brutally marooned

by a sadistic enemy.

Two hundred died the first night.

In the morning, the survivors knew what
they must live for—revenge!