It is on my 'Top 3 Favourite Smells' list.
I'm pretty sure 'blasty' is a Newfieism. You can find it in the Dictionary of Newfoundland English. It refers to when the leaves of trees are at their life's end, changing to yellow and red as they die.
Larch trees are unique in that they are deciduous coniferous trees; they have needles and cones like other coniferous trees yet they loose their needles (leaves) in the fall like deciduous trees such as maple.
Larch is also know as tamarack, however locally it is often inaccurately called juniper.
Interestingly, we do have a plant here named juniper. Confused yet?
Juniper is a low, sprawling evergreen shrub that has a blueish berry. If you get the chance to taste the berry you will find it reminds you of a wonderful and marvelous thing...gin! Juniper berries are actually used to flavour gin....a ridiculously good berry indeed!
Coniferous, deciduous, whateverous...it all adds up to a lovely smell this time of year! It doesn't take too long for the blasty bough smell to disappear from the woods though. Pretty soon, a light covering of snow will dampen their sweet mustiness. Yikes! So, enjoy it while you can!
My favourite books about local flora...very useful!