Thread by @ZimermanErik

Massive forest fire has broken out south of #Andriivka (Kharkhov oblast), due to #Russian shelling. This intensity of fire ensures that in this sector, UA forces have been forced south of the Siverskyi donets river. This is an important part of the front, as RU forces have tried

to push #Ukrainian forces south of the river and away from the main R78 highway and more importantly the railway (#Izium - #Kharkhov). UA forces have learned to very stubbornly & effectively cling to forested areas. In fact most of the active front today is along the forest belt

between Kharkhov and Lugansk. UA forces do not do well in open terrain, nor do they wield field units that can maneuver in them, but they do defend doggedly in urban centers, prepared entrenchments, and dense forest. The combination of the long river and dense forest on its banks

have slowed down Russian advances considerably. RU is near overcoming these obstacles at several key places. The capture of Sosnove (along with earlier Yarova, Studenok and the Oskil forest area) has been an incredibly underreported event of strategic importance. The forests

Oskil were very stubbornly defended by the UA forces for a reason, in fact forces were left behind there even once they were encircled, and delayed Russian control of the are for weeks in total. The prize was this key rail junction. As much as Izium has been rightly hailed as the

first breakthrough point (through the forest belt & river) and then supply hub for further RU advances southwards, the supply lines have been mostly road based and too long for Russia's truck system. The railway from Izium does not go northwards but west and NW towards the

Kharkhov region. While it does loop around potentially (at Zanky) towards Russian-held territory, the continuous line is not held by RU forces. It is only by linking Izium with the station at Sosnove that RU obtained a real rail link northwards to its main supply hub at #Kupiansk

A railhead hub nearby makes all the difference in the world in the possible pace of operations for the Russians. This is why recently, the forces around rail-linked Yarova and Sosnove are powerful & the crossing (commented on in my earlier threads) was successfully attempted here

The same thing will extend to Lyman, Yampil (and eventually Siversk when it is taken) as those rail supply lines are fixed and set up. Now rail connected, Izium can project further strength west to clear the main (R78) highway and rail line towards the Kharkov oblast.

Fortified UA held Andriivka is the main obstacle here, and this heavy shelling (and mass fires) behind it in the dense forest weakens the position and allows RU forces to get behind it. RU troops control Balakillia & some territory west of it, & are now shelling the wooded areas

south of the highway to push the front line beyond the river and get the road and rail lines out of fire control range. Because this advance westward (while clearing south as you advance west) is along the main highway and rail line, it will now proceed with greater strength.

If the way is cleared all the way to Zanky, which connects with another line northwards, then the Russian logistics will be improved in this entire sector of the front, between Lugansk and Kharkhov. It will also increase Izium's capacity by a double track rail line instead of one

single track, which will be important as that line feeds hubs further east such as Lyman and Yampil.