ND said ..." I also wouldn't worry much about the larger the acorn the larger the seedling. We collect thousands of acorns a year and have never seen a huge difference in this. Even if the two different sizes are collected off the same tree."
There is some evidence that bigger is better ... especially if the acorn is damaged after planting. The evidence ...
A study at the Croatian Forest Research Institute
found that bigger acorns produced taller saplings with more bio-matter (in non-technical terms, they weighed more). This was confirmed in a follow-up study by the Serbian Institute of Forestry
(692KB, PDF). It is therefore reasonable to conclude that acorn size does matter, with larger acorns leading to larger saplings. There are no studies on what happens next, and whether this benefit is carried throughout the tree’s life. However, we believe it’s likely the benefit is only an early competitive advantage, and that growth rates will even out as the trees mature and they are subject to less selection pressures. They say .... "So there you have it, acorn size does matter, at least for early growth!"
. 2015; 5: 8112.
Published online 2015 Jan 29. doi: 10.1038/srep08112
Damage to seeds has been found to cause decreases in germination rates, reduction of seedling performance, and even death of seeds or seedlings13
. Fukumoto and Kajimura15
show that survival of hypocotyls and radicles of Quercus variabilis
is severely affected by high-level cotyledon loss. Kennedy et al.16
found that seed reserves have an important effect on the early performance of Lithocarpus densiflora
seedlings. Cotyledon removal just after the emergence of seedlings poses significant negative impacts on seedling growth of oaks17
. (persons who remove the acorn shortly after germination to reduce damage by predators may be making a mistake - my observation; not part of the article)
. Significant consequences of cotyledon extirpation of seedling growth in oaks have been widely observed in previous studies18
. Existing literature indicates that energy reserves in cotyledons play an important role in supporting seedling development; therefore, damage to seeds can negatively influence seed survival or seedling development
. Our data showed that post-cut acorn mass, rather than initial mass, appeared to be a better predictor of seedling performance (e.g., seedling height, leaf number, seedling dry mass). At lower levels of cotyledon damage (<60%), large acorns showed no advantage over small ones with respect to seedling dry mass. However, seedlings from large acorns appeared to perform better than those from small ones at higher levels of cotyledon damage (i.e., 60% and 65%), partially supporting our prediction that large acorns sustain damage to cotyledons better than small-sized acorns.
This last paragraph is included simply to demonstrate they used widely accepted statistical measures to produce their results.
"We used Statistical Package for the Social Sciences (SPSS 16.0) for data analysis. ANOVA was used to determine if there were differences in the initial (post-peeling mass) and post-cut acorn mass between the control and treatment groups. One-sample Kolmogorov-Smirnov test was used to determine whether the dependent variable was normally distributed. Linear regression was used to determine if initial mass (independent variable) of an individual acorn predicted the final total biomass (dependent variable) of the resulting seedling using only control acorns. Linear regression was also used to determine the effects of post-cut acorn mass and percent acorn damage (dependent variable) on germination rates and seedling performance (dependent variable). Linear regression was also used to determine the correlation between seedling dry masses (dependent variable) and exact cotyledon loss amounts (independent variable) in all treatment groups, to see if large acorns tolerated cotyledon damage better than small ones. Cox regression was used to test the difference in acorn removal rates between large and small acorns following arc-sine transformation."
Sorry for the relatively long post