Most stars form and spend their early life in regions of enhanced stellar density .
Therefore the evolution of protoplanetary discs ( PPDs ) hosted by such stars are subject to the influence of other members of the cluster .
Physically , PPDs might be truncated either by photoevaporation due to ultraviolet flux from massive stars , or tidal truncation due to close stellar encounters .
Here we aim to compare the two effects in real cluster environments .
In this vein we first review the properties of well studied stellar clusters with a focus on stellar number density , which largely dictates the degree of tidal truncation , and far ultraviolet ( FUV ) flux , which is indicative of the rate of external photoevaporation .
We then review the theoretical PPD truncation radius due to an arbitrary encounter , additionally taking into account the role of eccentric encounters that play a role in hot clusters with a 1D velocity dispersion \sigma _ { v } \gtrsim 2 km/s .
Our treatment is then applied statistically to varying local environments to establish a canonical threshold for the local stellar density ( n _ { \mathrm { c } } \gtrsim 10 ^ { 4 } pc ^ { -3 } ) for which encounters can play a significant role in shaping the distribution of PPD radii over a timescale \sim 3 Myr .
By combining theoretical mass loss rates due to FUV flux with viscous spreading in a PPD we establish a similar threshold for which a massive disc is completely destroyed by external photoevaporation .
Comparing these thresholds in local clusters we find that if either mechanism has a significant impact on the PPD population then photoevaporation is always the dominating influence .