In this area, I have to contend with the sun and vegetation, which is why I would prefer a long sleeve top.
In terms of the vegetation we have this brush which has thorns that are curved. It won't cause harm, but it'll break skin and leave some good scratch marks. We also have the normal pointed thorns, but they don't do as much damage as the previous. Having long sleeves can prevent from having bleeding arms. But here's the flip side to having extra material, we have burrs that stick to almost anything and everything and one of these burrs has small thorns which will annoy you all day if not removed.
For sun protection it's nice to be covered up and not get burned. Sun and heat is always a tough combination. In my opinion, vents and mesh are the best for ventilation, but then it may not have any UPF ratings (UV Protection).
Another reason why I prefer long sleeves, is because if I select the right material, I don't have to worry about the "shine" coming off of my skin.
Here's a look at the Scorcher Top and below is the description from the company.
The ultimate warm/hot climate top. The Summer top is constructed from fabrics with air flux technology, manufactured to maximise breathability without sacrificing durability.
AIRFLUX fabric technology with microscopic pin-holes to allow unrestricted air flow, keeping your skin cool in the hottest conditions. 100% polyester composition for super fast drying time, keeping you light and dry.
Lightweight and ultra-quiet fabric by Toray. Microscopic holes throughout maximise air-flow and evaporation. Perfect for the active hunter - keeping you cool, dry and comfortable in the hottest conditions.
-Flat lock stitching
-1/2 front zip
-SILENTSLIDE YKK zippers
-4 way stretch
-Air flux fabric
-Anatomically fit shape
-Thumb Loops