Trees growing in open environments may not self-prune, and branches often bend downward to reach the ground.

It may occasionally reproduce by layering in bogs, sand dunes, and some high-elevation forests when moisture availability is particularly high.

Germination may be higher on disturbed soils or where seeds are shallowly buried in litter. It establishes on various substrates, and one study found all seedlings growing on rotten wood.

Shade tolerance may be highest for seedlings and decrease as trees mature.

Its relative abundance and dominance may change over time, depending on plant community and site characteristics.

It does not resprout after injury or top-kill, and postfire recruitment is limited by a transient seed bank and short dispersal distance. Seedlings and small trees are likely to be injured or killed by fire.

One experimental study found no survival of 89 germinants on burned litter after 1 year.

Postfire mortality likely depends on the degree of injury sustained, such as the amount of cambium killed or the percentage of crown scorch.

However, after logging, its needles remain on twigs that dry quickly and can ignite explosively when dry, and its slow decay can build heavy fuel loads.

However, seedling survival seems to be low, and its short dispersal distance limits establishment in large, high-severity burned patches where no mature trees survive.

For example, fire exclusion in fen communities can allow Port Orford-cedar to establish and spread into fens, but excluding fire from frequent-fire forests has densified stands and shifted them toward high-severity fire that is more likely to kill it.

Where it is most common (North Pacific forests), LANDFIRE models estimate historical mean fire intervals over 400 years. Elsewhere in its range, estimated fire intervals are much shorter, from 8 to 68 years. In drier forests with short estimated fire intervals, it mostly occurs in moist microsites, where fires may be less frequent than the surrounding area.

Elsewhere in its range, models estimate that most fires were mostly low- or mixed-severity. In drier forests, Port Orford-cedar mostly occurs in streamsides and other moist microsites, where fires may be of lower severity than surrounding areas.

However, its wood is decay-resistant, so mortality agents—particularly the nonnative pathogen Phytophthora lateralis—may increase dead-wood volume, and its slow decay rate can build heavy fuel loads where fire is excluded or infrequent. Fire exclusion has altered fire regimes and forest structure across much of its range, but Port Orford-cedar density was not described as altering fuels.