Tsuga heterophyla seedlings can grow very well in deep shade, even in the shade of our Pseudotsuga menziesii old growth forests, where it will eventually prevail if no disturbances like fire or major blowdowns occur. It squeezes out the Doug fir seedlings.
Mike

How come that inspire of a seriously dry summer, which was hot too a Tsuga standing on top of a very sandy dune does so well (under a very open pine stand), but other trees suffer? It is not shady at all there, I'd say it receives 70% of sun if the sun shines all day...I thought drought was detrimental to Tsuga, but may be it is a combination of nutrients and drought. It is a poor sandy soil too and Tsuga can grown on very poor soils. The other species may be not so much...Having said that: in a year with normal rain Abies grandis which is there too put on 1 m or more (20 year old trees, not saplings)....

I just don't know how Tsuga can actually thrive this years and none of the others really did.

You may simply have gotten lucky with a Tsuga seedling with good genetics.

Maybe-and I'm only partly in jest here-some fanatics are at work in the area in question, killing those nasty invasive plants. I have heard of such activities in some corners of Europe. Otherwise, we sometimes have to face the fact that we just don't know why this one survived, that one's dead, and the other one is so-so. I've seen perfect and perfectly happy young white pines just up and die. No discernible reason, it just happened.

+oM

Tsuga heterophylla commonly grows on the top of old Pseudotsuga menziesii stumps and 'nurse' logs here. It's uncommon not to have some growing on a stump. Maybe that's why they can grow on a sand dune in the Netherlands.
Mike

First of all thanks for the responses. Genetics...could be, but do note none of them did bad really.

Native plant activists? Are you kidding me? People do not tend to be so fanatic, otoh one Arboretum in my city first got help but then was refused because it would be growing Sitka spruce etc. I read that. But seems very rare. In the forest they ar eindeed active getting rid of the Pines btw. Because they do not bnelong in dunes. But the pace, according to the forrester, is laughable. Just one you guy with one small machine has to take care of it. Behind his back the Pines sprout all over the place. Also: They leave Abies grandis, Sitka spruce, Norway spruce etcetc alone. I have seen them cut down pine, with these species now standing in the sun alone. Nice view actually. So that is not it. The others are also dead while those next to them are standing, I think it is dear browsing etc.

It is standing one sanddune covered by forest btw. Not a barren dune. Lots of woods debris in the soil, as some pines were cut down (they leave the dead wood). So Imay be I should be mre clear.

Finally: I can show you pics a la Pine Resin with loads of Tsuga seedling and none of them on any nurse logs. Indeed, not necessary here and I did not witness nurselog syndrom in Scotland either (only in the western paert at Pucks lodge I did witness nurslogs). FInally: I do see spruce and pine seedlings on nurse logs...

So...may be it is genetics, but I guess the fact that the place is litered with pine debris means it gets enough nutrients to survive the drought...

Here we have norway spruce, sitka spruce, western hemlock, Douglas fir. Abies species. And lots of hardwoods.

Very funny to see that again Tsuga was doing just fine. Green. no problems. Doug fir identical. European Fir: just fine (browsed heavily). Norway spruce: did not find any seedling, but the mature trees were all fine.

Now sitka spruce. This place has a sandy part and a sandyloam part. Seedlings had top dying in the sandy part big time, but new growth emerged from the basis. Seedling were 30-50 cm mostly.

Elsewhere in the in between zone a funny thing happened. One seedling had grwon really well. a uch larger specimen 20 cm to its right was dead with new growth sprouting out from the stem! Strange.

On the loamy site everything was fine. All sitkaseedlings did very well. The warmth must have been to their liking, the drought was alleviated by more moist in the ground. Doug Fir and occasional sitkaspruce were browsed though. Top was browsed, non was dead.

So as expected: ground with better moisture was just fine for all conifers. On the loamy soil there were also far more sitka spruce seedling than elsewhere. The palce was actually littered with Sycamore, a very resiliant and fast growing tree. But it did not grow where Sitka did (more in the shade). The sitka part only may be 20* 20 m parts weres o different: instead of grass very moist and with thick moss layers. Some blackberry, lots of ferns. Just a typical spruce forest floor in minipockets. Fun to watch!