Grass Wood YWT


Site Details:

Recorders: Blomfield, Ian and Barbara Distance: 1970m Altitude 283m. Walk Time approx: 50mins

Grass Wood is one of the largest areas of broadleaved woodland in the Dales and one of its richest. It is just to he north of Grassington village. It is situated on the west and south facing slopes of a bench of Carboniferous limestone, and so the woodland grows out of limestone scars, limestone pavement and scree. Beech, sycamore, spruce, larch and pine were planted into the woodland in the twentieth century and these are gradually being removed to restore the wood to its natural canopy composition of ash, wych elm, oak and hazel. The ground flora is particularly species-rich including lily-of-the-valley, stone bramble, mountain melick, common valerian, wild angelica, salad and great burnet, melancholy thistle, lady’s-mantle, angular Soloman’s seal, common rock-rose, bloody crane’s-bill and betony. It has a very rich butterfly and moth fauna including Norther Brown Argus. Bastow wood immediatlly to thr east is another extremely good site with a large population of NBA


It is section 3 before the butterfly numbers beging to climb with Speckled Woods predominating along with Ringlet. S5-S6 grassy south slopes into the small valley is where Northern Brown Argus begin to be seen and the highest section totals counts along with S8 is teh most wooded section with lareg numbers of speckled woods . The slope back into teh valley at S9 also sees Dark-green Fritillary and NBA . The damper valley bottom of S10 and 11 yield much larger numbers as you would expect of Green-viened Whites and even Orange Tips.

Results: 2021

2021 was up a very large 25% against teh average and well up on last year and and not so far away from the cracking year 2019. Only teh skippers were down which they were in many localities , Interestingly the whites, the vanessids, northern Borwn Argus and dark green fritillary were all up bucking the trend over most of lowland Yorkshire. Its great to see the threatened species small heath return. In terms of numbers most of the increase is down to Ringlet and Speckled wood both having their best years since 2019. This is one of the very few sites that saw Peacock increase. The reasons are likely the temperatures were much less extreme here than in the lowlands and may not have experienced the drought.

Transect reports

Results: 2021

2019 remains an outstanding year and has a big influence on the 5 recorded year average not helped by the absence of results from 2017 and 18 , a period of quite quick changes in habitat by 2019 easily seen by the very large number of Speckled Wood and Ringlet . However we can say 2021 was a little down on 2020 mostly because there has been a dip in these two species along with the whites. Northern Brown Argus and Green Hairstreak reappeared in 2020 and is being maintained. brimstone did very well as it did in most transects . Dark-green Fritillary also maintained good numbers. From the rarer species point of view it is an improving picture.