  Ground assets deployed in a cluttered environment with randomized obstacles
(e.g., a forest) may experience line of sight (LoS) obstruction due to those
obstacles. Air assets can be deployed in the vicinity to aid the communication
by establishing two-hop paths between the ground assets. Obstacles that are
taller than a position-dependent critical height may still obstruct the LoS
between a ground asset and an air asset. In this paper, we provide an
analytical framework for computing the probability of obtaining a LoS path in a
Poisson forest. Given the locations and heights of a ground asset and an air
asset, we establish the critical height, which is a function of distance. To
account for this dependence on distance, the blocking is modeled as an
inhomogenous Poisson point process, and the LoS probability is its void
probability. Examples and closed-form expressions are provided for two
obstruction height distributions: uniform and truncated Gaussian. The examples
are validated through simulation. Additionally, the end-to-end throughput is
determined and shown to be a metric that balances communication distance with
the impact of LoS blockage. Throughput is used to determine the range at which
it is better to relay communications through the air asset, and, when the air
asset is deployed, its optimal height.
