Wisconsin Marten

I'm just thumbing through The Wisconsin Trapper magazine that came in the mail today. There's an article about our efforts about marten restoration. It seems in places in Eurasia where they were introduced they really took off but here in Wisconsin which is in their original range they are struggling.

Are these critters just not adaptable? I would think we would be able to breed more resilient and fertile varieties.

Marten need unfragmented contiguous forest with good overhead cover-80% or better and lots of coarse woody ground debris.Also standing large dead chicots are important for nesting.This is core marten habitat.They will use other habitats but need the core areas connected.
Fragmented forest means after the population lows the habitat cannot be readily populated from core areas before the next low.

I would surmise that your forested areas in Wisconsin are too fragmented to sustain good marten populations.

The 80% cover is to protect from raptors?

Not sure what a chicot is.

You are not going to like this, but it is hard to set baited or lured traps for anything where marten are and not catch marten.

That's true. My Son Bridger and I caught a dang marten in a coyote set in Wyoming.

I suspect there may be some validity in Boco's post about undisturbed areas.

Also, what other critters are in the area that will compete with marten. Fisher ? Fox ??

What is in that area for them to eat ?

Marten are NOT receptive to breeding in captivity so trying to adapt them in captivity is not likely to be successful

The overhead cover is assumed to give them some protection from raptors,but I believe there is more to it than that-more to do with the shade on the snowcover to keep the subnivean environment conducive to hunting.

Chicots are standing dead timber in mature forest

I live very close to a marten restoration zone. They seemed to be doing well until fisher were reintroduced into the same area. Now the area, mostly designated Wilderness, is awash with fishers. Maybe that has something to do with it?

Yes there are only a few places in Ontario where both fishers and marten both do well and that is in central Ontario.
Where I am there is not an overabundance of fisher so marten are the predominant species right now.
In the 1940's there were very few marten but a lot of fisher in this area according to the old timers I have spoken with like Paul Millette.
South eastern Ontario is polluted with fisher and there are no marten.

Wisconsin Marten Management Plan

American marten abundance is greater in areas of northern Minnesota and the Upper Peninsula of Michigan than in Wisconsin. Scientists from these other states have recently observed or suspected a decline in marten abundance, which has resulted in a reduced harvesting season in Minnesota. Most martens trapped in both states are from areas of high snow fall and snow pack depths and landscapes comprised of greater amounts of coniferous forests (e.g., spruce-fir forests).

Many of these scenarios should have little effect on martens, but the significantly reduced snow pack levels predicted are the exception. Notaro et al. (2011) predicted a 21-29% decrease in snowfall and 48-68% decrease in snow pack levels in Wisconsin by 2050. This result would substantially decrease the foot-loading advantage martens have over other carnivores during winter and likely increase predation rates. Consistently reduced snow levels may eliminate the competitive advantage martens have over fishers

They have been flushing money for years down the Marten toilet. But It's keeping some researcher's employed.
We just don't have the habitat nor the food base here In WI.
And I believe that you can't use foot hold traps those marten recovery areas.

I think you can use foothold traps but they gotta have at least 4 lbs of pan tension. I could be wrong though, I don't pay much attention to those rules because I don't trap there.

Maybe there was historic record of marten in WI but what is that record? One sighting? A bunch of furs that were sold? Basically, what is the magnitude of the historic record that they are using to support their reintroduction?

Based on their success it would seem best for WI to admit they don’t have boreal forest (because they really don’t) and to abandon marten as a project.

I agree with what others have stated . Here in NY’s 6 million acre Adirondack Park the Marten have expanded their range right up to the Black River Valley, that separates the ADK’s from the 2100 square mile Tug Hill Plateau. Many experts say the fisher population in the ADKs are in decline and maybe that is why the Marten are prospering there ? Tug Hill seems to have the habitat for Marten, however Tug Hill is awash with fisher, and I and DEC Biologists think that is what is inhibiting the Marten from gaining a foothold on the Hill.

BOCO what is your bobcat population? It seems here in Pa our bobcat population is decreasing with the increase of the fishers. I might be wrong and maybe there is no relation between the two and just my observation. My little bobcat hollow (as I call it) now has fisher and no cats are there??????? Just a one person observation........jk

Competition for food is a big factor, I recently moved from the Park Falls area and the over abundance of cats had the fisher numbers way down, I quit applying for tags years ago. I have no idea what's going on in the Clam Lake Martin restoration area, I seen one Martin in 15 years, seemed to be plenty of cats, but no idea on fisher. Maybe they changed it but there was no land trapping in the Martin restoration zone. The four pound rule would at least allow some predator trapping, if true.

I sorely wish the martens around here would listen to all this stuff about 80% cover, chicots and areas of high snow fall and snow pack depths and landscapes comprised of greater amounts of coniferous forests.

We have practically none of that. Yet, since they secretly reintroduced them, in the east (No body admits to this. It's just not talked about. But, their last known toe hold was in the far west.) Now, they're spreading like a plague, west and heading south.

We're tripping over the darn things here and they're totally protected by law. Can't even look at one sideways. And, yes; They thrive in just about every type of environment we have to throw at them.

Definitely habitat dependent. Areas here in Michigan where I can almost guarantee a marten in our short limited 9 day season, but 5 miles away I've never seen trace of one.

Granted, I have caught them in open mature hardwoods, but there was black swamp and/or edge habitat within eyesight.

As usual Boco is spot on with his description of habitat.

This is a very interesting observation.

And some guys in Idaho and Wyoming are starting to encounter marten in riparian zones in sage brush country. Perhaps marten are adapting/evolving to new habitats simultaneously around the globe.

Coyotes in North America seemed to adapt almost overnight to urban environments during the 1970's. And wolf populations have taken-off globally in the past decade or two.

Not sure If Ontario even has a bobcat population I trapped there for 7 weeks and caught 5 Lynx but never saw a bobcat track . My buddy who I traped with In Ontario had to come to South Carolina to catch a bobcat and a grey fox .

Bobcats in Ontario are along the north shore of lake Huron from about the Soo over to about Temagami and south to about Marten river.That corresponds with the southern range limit of lynx.Bobcats are not overabundant,but some are caught every year.
I skinned a hybrid lynx/bobcat at north bay once that was brought in for the convention.It was caught North of Sturgeon falls.

We have Lynx and fisher where I am but no bobcats.

Your fisher could be outcompeting the bobcats for prey like rabbits.

Fisher dont have that advantage over lynx because lynx can navigate the deep snow much better than fisher so have no problem competing with them for rabbits in winter.In fact one of the reasons why fisher are not that abundant here is that they have a tough time competing with the high numbers of lynx here for the food supply in winter.

But........Pest's Dad is also talking about a different species of marten. His is the European pine marten whereas ours are American marten. The two have developed differently over time and may be specifically adapted to different habitats.

Why is this discussion reminding me of one of my Fish and Game Advisory Committee meetings? I have had ADFG present all the information and no body reads it and we waste hours on war stories, and speculation.

^^^^^^ (White17)
But maybe martens are starting to show some degree of adaptability. We generally think that adaptations occur only over long periods (eons) of time; but maybe that is not always the case.

I will hypothesize that animals that are generalists, like coyote and wolves, have a greater likelihood of relatively rapid adaptation, versus animals that are specialists like lynx.
Where do marten fit (generalist versus specialist) I don't know. However, unlike lynx, marten do have a broad range of things that will satisfy their diet.

The main reason marten here have adapted to avoid open country

Bob Noonan opened my eyes to the avian predator idea a few years ago while talking at a convention. Changed the way I scout for marten for sure.

I agree with most of that Waggler.

It also occurs to me that canines can populate much more rapidly than mustelids. Why ? Because of much earlier sexual maturity in canines and far larger litters than in the mustelids, and much shorter gestation periods in the canines. Also, the predation rate on martens is likely higher than on canines.

I would theorize that adaptations can take place more rapidly if the rate of recruitment into a given population is greater.

Also canines generally cover larger territories than marten........probably because they must and partly because they can.

It just seems to me that marten have so many highly restrictive criteria associated with their breeding and habitat requirements that it should surprise us when we see an abundance. IMO they are an extremely complex critter.

Maybe Gulo will weigh in on this

^^^^^^
I certainly agree that marten are a complex and somewhat mysterious critter.

I remember a few years ago I scoffed when I heard that they were introducing marten into the Black Hills of South Dakota. I've driven through the Black Hills, and it sure doesn't look like marten habitat to me, it seemed much too dry. However, to my surprise, I hear they are having some success.

"Harvest estimates in these areas were 2,073 in Minnesota (Erb 2010) and 290 in Michigan (D. Etter, Michigan DNR, unpublished data) in 2009."


" In 2007, 499 trappers spent 4,407 recreational days trapping martens in Michigan (Frawley 2008). "

Looks like half a marten a year? I know different years.

Yeah when I picture the area around Rushmore that doesn't seem like marten country to me. Not because of the dryness but because of the relative openness of it. The trees are fairly far apart . On the other hand, there are turkeys there so the cover must be reasonable.

I don't think marten would be real dependent on water but I think you mean as water pertains to foliage ??

Be careful what you wish for. With marten reintroduction and successes will come trapping restrictions on other species that are far more profitable when you are limited to catching a few marten.

If you don't have the restrictions, marten populations probably won't do too good.

Black hills management plan

"The factors most likely to be limiting to martens in the Black Hills are extensive cutting of white spruce forests, fuel wood cutting in or near spruce-dominated stands, high-intensity fires over large areas of spruce-dominated forest, and weakly regulated trapping."

As usual, I'll embark on a brief session of verbal diarrhea.

I certainly agree with the above post from white17 that animals with generational periods that are relatively short, can, and do, evolve quicker than critters with longer generational periods. Contrary to the common line of thinking, animals do not genetically adapt to changes that they encounter in their environment. Rather, those adaptations are occurring constantly, whether the habitat is changing or not. The vast majority of those genetic adaptations are actually maladaptations, and those individuals don't do any better at surviving and passing on their "bloodline" to their offspring. If those genetics are indeed maladaptations, that individual often falls out of the gene pool, never to pass on those genes. Every once in a while, the chance genetic change is actually beneficial to the individual, and its chances of living a long and healthy life are increased, thus the chances of contributing offspring increases, perhaps also carrying that beneficial gene. Thus changes are constant. For animals (marten, for instance) with small litter sizes, long gestation periods, delayed adulthood, those changes in their genetic make-up take longer periods of time to become commonplace among the overall population.

I was contacted some time ago about transplanting marten to a couple of sky islands in Nevada. Apparently, there was evidence that marten previously inhabited at least a portion of those sky-islands, and NDOW (Nevada Fish and Game) wanted to re-introduce them. Before getting involved, I first asked if monitoring would take place, and if the transplants were successful, would trappers be allowed to harvest. NDOW assured me that yes, that was the plan. They had done some preliminary work, and it appeared to me that there was probably sufficient food resources to sustain marten populations. During the course of numerous discussions, I asked which species of marten they originally had, and was that the species they wanted returned? My question was met with deafening silence. I'm outspokenly in denial over the recent splitting of marten in North America into the two species (American marten, Martes americana and Pacific marten, Martes caurina). In my opinion and research, the differences between these two critters is negligible, and certainly not enough differences to warrant distinct species (but that's an entirely different discussion). Through another couple of years, I got no more inquiries about doing the work, and I assumed the potential program simply died on the vine.

The reason I bring this up is to illustrate the variability in what habitats and conditions marten are able to survive and prosper. Yes, the Dakotas don't seem to be country that I would call decent habitat. Likewise, neither is the habitat that waggler mentioned (the thin willow riparian bounded by desert sagebrush, in which I currently trap marten). Consider some of the most productive marten habitat in North America. The temperate rain forest of SE Alaska is phenomenal marten country. Likewise, the extremely different taiga of interior Alaska is very productive marten country. These habitats are like night and day, yet marten seem to have adapted quite well.

I've spent a lifetime trying to understand predator natural history. I've done years of research on marten, mink, river otters, wolverines, and badgers, as well as several non-Mustelid predators (Ursids, Felids, Canids). I've also spent that same lifetime trapping those mustelids. I'm forever astounded at what we still don't know. Marten, in particular, are somewhat of an enigma, in that biologists and trappers alike have not figured out most of the factors influencing their populations, and we still have a poor understanding of how to manage for sustained high populations. I wholeheartedly agree, marten are complex and mysterious.

Jack

Love your insights , Jack. All the time.

Your thoughts sent me right to those other threads about this subject, on the Wilderness forum some time ago. I enjoyed those comments from everyone immensely.

I still am pleasantly surprised at the varied terrain people find them in, for example, yours .

From my hat furs, I do agree that amazing marten are trapped in SE AK. And other northern areas too. Russia is a whole 'nother subject, too !

I smile every time I see your experience with the NDOW. Still crickets ....

Thank you for your valued input .

Wow I didnt think this would be such an informative thread. Thank you to all the contributions.

Surprised after these centuries no in introduced European marten or russian Sable.


I also know more niw about marten breeding. In amazing that they produce any offspring considering the things I've read.

That's the problem they don't here In WI.

"A live-trapping and track count study was conducted from 1983 to 1985 in and around the Nicolet Marten Protection Area (MPA) to estimate marten abundance and distribution after reintroduction (Kohn and Eckstein 1987). Eighteen martens were captured during this study, but none were recaptures of released animals. Thus providing good evidence that the population was reproducing. "

Your post reminds me of the movie Gorky Park. It was a rather complex movie with a lot of subplots, about an attempt to smuggle live sables out of Russia. However, if I remember correctly the "sables" shown in the movie were either Baum marten or European pine marten (large orange throat patches).
This movie came out in the late '70's I believe.

Yep. I can confirm the big, yellowish orange throat patch on the pines. One time, years ago now, the birds told me there was something amiss. Next thing ye know I'm tracking this big, buck mink along a waters edge, hundred yards away. Had him in the cross hairs and was just waiting for that still moment.

Then, all at once he stopped and turned to look my way. That throat flag seemed to fill my lens! I raised the barrel and thought how close I'd come.

That was years ago. Like when we'd still give a friendly nod and a smile of tacit welcome to a brown face in our tiny villages .....

. One of the reasons sited in Minnesota for lower fisher populations in certain regions is they are out competed by bobcats

Of the 45 fishers radiocollared, 14 are still being monitored (8F, 6M), 3 are missing, 10
shed their collars due to belting design failures, and 1 collar was removed at the time of
recapture due to neck abrasion. In addition, 3 juvenile males were ear-tagged only. Of the 14
known deaths (8F, 6M), 1 was struck by a vehicle, 1 was accidentally trapped out of season, 2
were legally trapped, 2 died from unknown but apparently natural causes, and 8 (6F, 2M) were
killed by other predators (scavenging by an eagle can’t be ruled out in 1 case).
Although sample size is small, all predation mortality of fishers took place from March –
May (Figure 3), and very rarely was any portion of a dead fisher consumed. Five of the 8
predation deaths, all females, were by mammalian predators. In one case, bobcat was
confirmed via trail camera placed at the site a fisher was cached. We are awaiting forensic
results for several other cases. Bald eagles are suspected in 2 of the 3 raptor predation events,
both of male fisher, though as noted above we can’t rule out scavenging in 1 case (only the
radiocollar was retrieved directly underneath an active eagle nest). The third raptor predation
involved a female fisher, likely attacked by an owl or hawk.
Of greatest significance, all 6 of the female fishers killed by other predators were adults,
and 5 of the 6 were killed while they still had dependent young in natal dens, indirectly resulting
in the death of their 14 kits. We suspect that energetic demands faced by adult females with
kits (i.e., lactation, and shortly after the energetically demanding winter) force them to increase
their activity in search of food, and preliminary data from temperature data loggers on
radiocollars suggests this to be the case. In addition, activity likely increases as a result of
breeding activity in the weeks following parturition, and all the increased activity occurs at a time
when concealment cover is diminished (i.e., before ‘green-up’), thereby exposing them to
increased predation risk. Regardless of the explanation, and acknowledging the limited sample
size, it seems unlikely that the high level of predation on nursing females is sustainable, which
may partially explain the recent decline in fisher abundance. However, the correlates to the
timing of predation mortality that we have mentioned are not new challenges for adult female
fisher, and the population appears to have been in decline only for the last ~ 6 years,
suggesting that other factors may be ‘altering the system’. It remains unclear whether the fisher
mortality pattern we have observed to date is consistent with past dynamics, and if not, whether
the underlying explanation is related to comparativel
y short- (e.g., periodic fluctuations in prey)
or long-term (e.g., deteriorating habitat quality) changes affecting fisher energetics/activity, or
relatively rapid changes in the predator community (e.g., the increased bobcat population)

Thanks Dirt. Great information.

Jack

Has anyone seen 1 lately?

https://www.wpr.org/first-time-century-martens-spotted-lake-superior-madeline-island

Jim Woodford used to be in charge of the Wi Marten project, now retired. Dont know the biologist in charge of program who operates out of Rhinelander. I tried to get updated info on WI marten project from him but its like i never talked to him. So much for project manager. I was involved in the procuring marten from Mn to add new genes to Wis marten popluation. Some Michigan marten do cross over into Wi and breed with our marten. All the time and $$ that Ray Teske ( passed) and myself put into project and cant even get a update.

That's cool that you were involved. Thanks

This one watched me bait a bear bait. Forest co. October.. 23

My state has a marten re introduction program slated I am told. Not sure where it is at this point. I do know that with our hawk and owl population is quite high. And with them all protected I don't see a success is in store for the marten project just in that category alone. Most of our forested areas are broken up, have gas well roads, clearings, mined areas are reclaimed and established food plots etc.

Great browsing habitat for deer and elk but not much there for marten. I also can see coming some restrictions on trapping in some of the selected re introduction areas once that has started. There always comes a downside along with these funded projects. You will catch marten on the ground and in elevated trap positions so there is no stopping that.

In our big woods of the mature hardwood canopies will be open once the leaves fall and there are limited vast pine areas to give them good cover and protection. It is spotty at best. I have my doubts if they will flourish here and reproduce to become a sustainable population. I guess only time will tell.

We do have a good squirrel population and some rabbits and hares in some counties of the state, but our fisher population is growing leaps and bounds. We have a considerable population in and around where I live.

However, they are protected in our local zones. We also have a very good cat population, far more than many realize. They have certainly adapted and reproduced quite well. Many good trappers I know are catching 6 to 8 a season in a just a couple weeks that have to be released. I do that myself. We have a short season on them currently at one per season with a tag. Most of them are caught in canine sets as incidental catches.

Those of us old enough, remember when hawks and owls were managed like most other species. And there were fewer around. Now i can sit on my deck and see some kind of Avian predator with my binocs almost at will, whenever I look around. All kinds of hawks and eagles around here not many owls except in winter.

People here who still live off the land "manage"them.

This.
Marten need a lot more than trees and squirrels. Their needs are pretty specific, yet subtle and not necessarily easy to identify.
A big misconception is the need for squirrels; not really a big component of their diet. But diet and cover is just one of many aspects of what marten need to thrive.

Does anyone know their range and density in WI prior to being lost? There are two areas in WI that have been the base areas for our re-introduction. I have not read up about marten needs or habitat, so I don't know if the population density is too low for adequate recruitment and growth or not. We do have several blocks of wooded areas in northern WI that should be large enough for marten regeneration, but success has been limited for sure. What are flora and fauna differences between our northern mixed hardwood, pine, spruce, hemlock than what is classic boreal forest?

Bryce

I don't live in a boreal forest. I'm not sure that really is a requirement.

Geez you Alaska guys know how to have a "discussion". Well thought out responses based on scientific evidence and personal observation and not even a hint of a jab at one another. Well done Gentlemen!

I have read about the importance of red backed voles in good marten populations(maybe other voles in other places) and I believe they are more habitat specific as well and need deep snow packed loose duff to survive well. But as Gulo points out Animal population under great stress can sometimes make successful behavioral and habitat adaptations that they might not have if not forced. One example is the now Freeway Red-tailed Hawk population around the Mpls/St Paul metro. There is one sitting on about every tenth light pole because they have learned how to live in that niche and pass it on. But adaptation is not always successful for all species hence extinction.

In the Cascade Mountains of Washington, there is a distinct elevation line where marten just don't seem to descend below. That line is generally highest in California and gradually decrease as you go northward. In most of the areas I trapped marten in Washington, that elevation is about 3200 feet, some places (especially north facing slopes) it is somewhat lower. One place in particular was less than 2000 feet, but it was defiantly a micro-climate area.

The thing that is noticeable, is that the tree species generally change from Doug fir/hemlock to hemlock/true fir as you go up in elevation. As soon as you hit that zone of true fir (silver and noble), and it was in old growth, particularly with a lot of downed logs, you would then find marten.

These higher elevations have more precipitation and much more snow cover. but studies have shown that martens favourite prey, the red back voles lives in equal abundance in the lower elevation trees stands and the high elevation trees stands. So it's not the feed that is the limiting factor.

My opinion is that marten need a certain moisture content in the soil and their environment in general for some strange reason. Coastal range marten, which are quite scarce nowadays, are found nearly at sea level, but then that is a wetter environment. They are a finicky animal.

One thing that you have to remember when thinking about marten, unlike mink which breed in their first year of life, marten don't reproduce until their second year. And they generally have fewer kits than do mink.

X2, NY’s Adirondack fisher population is diminishing and the Marten population is expanding. Here on NY’s Tug Hill Plateau the fisher population is high, so few if any Marten. I caught 7 fisher trapping while deer hunting. Although I did see a Marten track here while deer hunting and others say there are a few here on Tug Hill.

I remember leaving the Herkimer trappers convention some years back headed home. I saw a road killed marten along the highway not very far from the fairgrounds. The first I had seen in the wild.

As far as the elevation thing goes..........where I trap the base elevation is around 350 feet ASL with a few spots reaching 1100 or so. The only time I see marten at the tops (above timberline) is when it is very cold in the valley. They move up to try to stay above the inversion. We've probably all seen that.
Your mention of different flora and moisture makes me think about all the time I spent trying to figure out why there were lots of marten on one end of my line and very few on the other. Same latitude, same altitude, same vegetation........BUT very different soil types. One end was rocky, sandy, mostly igneous terrain The other was loamy with mostly sedimentary and metamorphic rock. Much deeper soils that certainly hold moisture better than the sandy stuff.
The end with the better soil had a marten density (based on my capture rates) of probably 8 or 10 times what the other end had.

I agree with you that squirrels don't make up much of a marten's diet. Way back in the mid-1990's....Gulo set me up with a microscope at my line cabin to explore stomach contents of marten.

The overwhelming majority of pieces I could identify in the gut were red backed voles. There were parts of grouse feet and a very few shrews.....not many. I don't recall ever finding any part of a squirrel that I could identify. Could have been there but mixed in pretty well with other hair and meat

No doubt , DEC biologists recovered a road kill Marten in Rome, NY a few years back.

I suspect there's not enough old growth forest for them to thrive.

It would be interesting to know if fisher are hard on marten

I don't believe I've ever caught a marten in old growth. Now I've caught some in 100 year old second growth, but it has been logged so not true old growth. Majority of the marten I catch are in 25-50 year old timber. Of course I've also never caught a marten in hardwoods, because other than tag alder we don't really have them. But that is what I see the majority of them trapped in back east.

I talked to an older gentleman and he caught numerous Stone Marten in SE Wisconsin in Kettle Moraine State Forest, I think he said early 80's. I believe they were released from a farm, bred and thrived for a short time period; some say they exist today.

Squash,
Thanks for the input. When I left NYS and the Mohawk Valley 19 years ago (lived about 2 miles from the fairgrounds as the crow flies) there were no fisher sightings. Since then they seem to be all over.
Geographically for everyone else, the Mohawk Valley is a long way from good Adirondack marten habitat. But fisher were only about a 45 minute drive north. However, the Mohawk River a Barge Canal need to be crossed to get there.

Yes. I had a friend see a stone marten in west central Wi ~8 years ago

Cool Animals to trap.

If our marten re- intro is failing due to our lack of large blocks of mature old growth woodlands, I guess I will take that. If we want way more marten that may mean far fewer, deer, grouse, other small game and maybe even beaver as we will have far fewer areas of early succession growth like aspen, birch and alder. I will take the latter for preferred species. On the negative side, due to millions of private forest acres not being harvested and lower stumpage value even less in our public lands we are getting more mature forests which is detrimental to most species we value and the blocks are not large enough for marten to expand. Sort of a lose lose if you ask me.

Bryce

I guess when I refer to old growth it doesn't necessarily just apply to the age of the trees. It's more of a forest type; generally a mixed age stand, snags, downed woody debris (root-wads, windfall, etc.), and understory. Old growth forests generally have the right mix, along with moisture.

I'm curious what the tree species are where you are finding marten in healthy numbers, also I'd guess maybe mostly in darker valleys, and on north facing slopes rather than drier south facing slopes?

I've seen areas in the panhandle of Idaho where I wouldn't expect to find marten, but then in the same general area I've seen dark, damp valleys and draws with hemlock and devils club almost reminiscent of SE Alaska and the western Cascade mountains of Washington.

I have my doubts that a lack of large blocks of old growth is the reason for the failure there Bryce. So many other things can impact an effort like this.
There are guys up here in SE Alaska who trap islands where both deer and marten are fairly dense. I suspect that the high fat/protein available at or near the tide line has a big influence there.

When we have forest fires here they can cover many miles because no suppression is used. They just burn...sometimes for months. Those burned areas often produce good marten populations 2-5 years later. Especially around the edges of the burn when there is available cover/concealment nearby in the unburned perimeter. The new shoots in the burned areas produce bumper crops of voles and downed trees . Great spots for a marten to hunt.

If there is trapping allowed near where a reintroduction has been tried then I suspect that might have a detrimental affect. Marten can wander especially if they are short on prey in the home range. Perhaps.....just throwing this out there........the reintroduction area doesn't get enough snow when your temperatures get low. Marten need a very high quantity of calories relative to their body size/weight and living under the snow when it is cold helps them conserve heat. Also, they are living at the same level as their prey if they are eating voles and shrews. That saves them energy by not needing to travel as far to hunt.

It's an interesting conundrum for sure. Quite a complex set of variables, probably the single most important of which is food. Without adequate calories all the old growth in the world isn't going to save them.

I’ve talked to a tribal game manager that was involved in marten research over the years and he said predation by fishers was a big reason marten wernt taking off. Bobcat predation has drastically reduced our fishers which the DNR seems to be clueless about so maybe martens would fare better now unless this huge cat population preys on marten as well. It’s insane how long it takes to get a late season cat tag. Especially when right across the boarder Minnesota has 5 a year limit and still there cat population wen up right along with ours.